Keith doesn't think so, I don't think many other people are convinced, either. So perhaps this is another instance of "control nodes" on my part.
But basically, my thought process is:
1. Attacking is more exciting than defending.
2. People will often mistakenly think that a sufficient defense is to have a great offense. See also: zerg rush. They are gravely mistaken in this game.
3. People are inherently creatures of habit, and will only experiment when bored or when the stakes seem low.
4. With the most-scarce and non-replenishable resource in the game, Science, people are going to be particularly conservative and only pick things they know about because the stakes feel very high. They will pick things that help them in the part of the game they feel is most important, aka attacking. Who can stomach unlocking turrets when they're getting smacked around on offense already? And by definition, if you're not getting smacked around on offense at least some, you aren't doing it right.
5. With those things in mind, it's almost impossible to get people to unlock turrets, no matter how exciting they are made. Something that is more versatile (can attack AND defend? Cool!) will be more psychologically enticing than something that is 3x better at defending, since players will rightly worry that they might hit a brick wall on offense and not be ABLE to get more science in order to unlock more of... anything, really.
6. We can tutorialize all we want, but people are going to naturally do what they do. I
always unlock offensive stuff, and have only unlocked turrets so far in order to test them, and for no other reason. I'm as prone to this psychological pitfall as the next person, and I don't think this is a habit unique to me. We've observed similar habits over many games over the last 8 years.
7. The pressure of "do I spend science on offense or defense" is inherently a Not Fun decision (at least that's my assertion). At best, an expert player is stressing about the exact balance. At worst, a novice player is just going for what they assume is best and then paying dearly for it later. A few rare turtles may wind up with tons of defensive structures and find themselves unable to take planets to get more science, etc. The trap works both ways.
8. The decision of "what type of offensive thing do I get?" is a very fun thing, and the cost of a wrong decision is only so high. Similarly, the decision of "what's my next defensive thing to unlock" is interesting and fun, and could get people into "turret play" simply because they're not going to leave a resource sitting around that can only be used on defensive things. No tutorials required, it gets people to use both types of resources.
9. We already have a shared resource, namely metal, to balance between the two things. We already split fuel and power in order to make the pressure between offense and defense not so high, for many of the same reasons that I'm advocating here. Although, arguably this situation is worse than the initial fuel/power one was. The fuel/power thing was more to do with brownouts than anything else, IIRC, at least chiefly.
10. Lore-wise, there's nothing wrong with this. Entomologists learn more about bugs. Chemists learn more about chemistry. Etc. There's no reason these couldn't be something like "Defensive Tech Points" and "Fleet Tech Points" or something. Ditch the term science in general, perhaps. Whenever you get get what is currently x science, you would now instead get x fleet tech points, and x/2 defensive tech points.
11. This would also create yet another indicator in the interface that players need to be thinking about the offensive and the defensive game at the same time. Since we'd be moving things over to the side, we could in theory bring back the Attack number, too, incidentally, and put it and Threat next to each other with the two tech points above each other. We'd then save some other horizontal space not showing where you're being attacked but instead allowing you to mouseover this to see it. Then it's just waves, CPAs, etc, in the little unimplemented-so-far boxes of Eric's that go to the right of the top-left bar.