There's a reason why Dota has a reputation among many people for crazed snowballing being stupidly common.
Typically the people who say things like this, in my experience, are people whom come from LoL who played for a week or less, gave up, and went back to their game. I've never met a single person who has been playing DotA for years that will tell you that comebacks are uncommon. It does take a certain understanding of the game, and a certain level of competence of your teammates, but comebacks are very possible if you really want it.
Items that are less worthy at higher costs, for example. That's great and all, but if the carry on the other team is already super-fed, he probably doesnt care too much.... and will probably more than make up for the item's expensiveness due to all of the gold he gets from slaughtering your team. AND, every time he kills one, that player then LOSES gold, while he GAINS it.
Looking at this another way, however, lends a very different view. The person that keeps dying didn't have that much gold anyway, so he's not really losing that much. In addition, the "reliable gold" mechanic gives you gold that you can not lose on death, regardless of how many times you die. On the other hand, when members of the enemy team die, they're losing a LOT of gold since they have it to lose, and if you're ending their streaks, giving you even more than normal.
In addition, it's difficult to discount the items in DotA which are extremely cheap and cost efficient.
Ghost Scepter is a 1400 gold item that gives the user 7 to all stats, and the ability to
become immune to physical damage for 4 seconds. In other words, it doesn't matter how much farm the carry has. Once a squishy hero buys this, the carry could have 10x his amount of farm but can still do absolutely nothing to him for 4 seconds. Nothing even remotely like this exists in LoL. The squishy hero can still even use his spells during this time, stunning, disabling, or nuking the opponents. Yeah, he can't use his autoattack anymore, but if you're that behind in farm, it likely wouldn't make much of a difference anyway right?
However, the 4 second attack immunity lasts even
more than just 4 seconds, and I'll tell you why. Team fights typically last about 10-15 seconds in DotA before there emerges a clear victor. If a carry begins attacking you, then you turn ethreal, he's not going to just sit and follow you around for 4 seconds, he has to switch to another target. If he just sat and waited for you to become vulnerable again, he would waste so much precious time and DPS while your allies were free to run amok. So basically, after he switches targets, who knows how much time you get before you become the target again. It is EXTREMELY cost efficient in this situation, and I've seen it turn games around many times.
Then you've got items like
Cyclone Stick which put yourself or an enemy hero out of the battle for 2.5 seconds. It costs 2700, but it's separated into smaller, easily buildable pieces, and it's something I love to buy on casters/supports. Sure, LoL has Zhonya's, but it's even more expensive, and can only be used on yourself, not an opponent.
You've also got
Heaven's Halberd, an item typically built for STR heroes. It isn't that expensive, and yet it offers amazing benefits against carries. 20 Strength (equivalent to 380 health), 25 damage, 25% evasion from attacks (in other words, enemy attacks miss you 1/4th of the time), and an amazing active ability, which shuts down a carry's ability to attack for
4 seconds.
On top of that you have items like
Sheepstick, which admittedly is pretty expensive, but is core on many casters, and takes enemies out of the battle for 3.5 seconds, during which they are unable to attack, cast spells, and can barely even move.
This is even including all the heroes in DotA whose abilities are designed to shut down or counter carries, of which there are many, and many whose abilities go right through BKB as well. The amount of ways to shut down a heavily farmed carry in DotA are numerous, and you can completely any amount of farm with the right items and good teamwork.
Is it easy to do? Absolutely not. It shouldn't be either. The carry earned that farm and gear by playing smart and getting ahead through legitimate means. It would be ridiculous if he didn't have the advantage in battle by sheer virtue of being able to right click you to death, after an entire game's worth of hard work getting up to that point. That's what it means to be playing from behind though. Yes, you're at a disadvantage. Yes, it requires better teamwork than the team is ahead. Why wouldn't this be the case?
Having said all that, I do agree that using these items effectively does require a decent understanding of the game. In lower level matches, carries are certainly king. It kind of reminds me of my Homeworld 2 days. I was never very good at the game, but sometimes I would venture online to play it in multiplayer against other people. I enjoyed playing multiplayer team matches because I wasn't very good on my own. Well the most commonly used strategy was to rush a "late-game" tech, massive warships called Battlecruisers. They took awhile to get and required a lot of money and research, but once you had them, you could basically unleash unbridled destruction against your foes that was difficult to stop. They had a lot of health, did a lot of damage (understatement), and their slow speed hardly mattered because you could warp them wherever you needed them to go. Most of these matches ended one way or another in a BC war, with the team who built the most BC and used them the quickest, always coming out the victor.
Fast forward a couple years, and I decide to play HW2 again on a whim. Most of the newer players have already left the game and moved on to something else. I get into a game with what seems to be fairly experienced players, and they laugh at me as I try my typical BC strat again. They simple disable my Battlecruiser, take it out of the battle, then capture it with marine boarding parties. I was completely baffled. Afterwards they told me how noob that strategy was. I began to realize that these guys were on a whole different level than me, and looking back, I'm sure that had always been the case.
In terms of comebacks, I see those all the time in high level play. The International 2013 was just amazing with how many comebacks and upsets there were. I mean you could just see how *BADLY* some of those teams wanted to win. They were willing to defy the laws of ****ing nature to win those games, even when they were impossibly behind. I'll see if I can find some examples, but that tournament in particular was extremely impressive in that sense.
