Not really -- my last game I barely had any defenses, its just that it takes too much time to build up the economy needed to build a fleet capable of crushing an opponent, if he's even slightly capable.
Depends on what you do, I guess. The first thing I usually research is ice planet colonization (if I have those near me), then trade outposts, and I build a trade outpost on every planet I control. Even with 4 planets, the income from trade ships adds quite a bit of income I find.
Also, again, I'm posting this argument with the assumption that the general pace of the game will be increased in some manner, as the devs said they're looking into it. Whether it's just speeding up resource gathering or speeding up everything. That will help a lot.
I actually timed the difference between a single player game and a typical MP game (I've yet to see one without the jerky movement/lag, so that's typical for me). In an SP game, it took 1 minute 40 seconds just about to gain 50 antimatter on my colony ship. In a multiplayer game, it took slightly over 2 and a half minutes to gain the same 50. That's a huge difference for a little lag. The part that worries me is that presumably everyone's hosting on either DSL or Cable, which shouldn't in theory be laggy like that.
But anyway, I think a lot of people are panicing with the current pace, and proposing some pretty drastic changes that I think are unnecessary. I say wait until the devs do what they do with the game pace, and then we'll see how much it improves.
Also, it doesn't take that much to build up a "fleet", a single cap ship, 10ish Cobalts and 10ish LRMs can do a lot of damage if accompanied by a couple of siege frigates. That's not a huge fleet, nor does it take huge amounts of resources to build. Presumably you will be attacking while your opponent's fleet is tied up somewhere else