I would argue you can switch places of the two words “Build” and “Speculate” and still come up with accurate statement. In essence both are needed. Those who speculate motivate building, those who build motivate speculating.
Speculating successfully and consistently is as difficult as building, perhaps even more.
Maybe I've just connected with too many speculators who can nail things pretty consistently. They have more money to put at risk, but even with a high fail rate, they do very well. Maybe it's just the DeFi craziness going on right now, but the same could have been said for the 2017 ICO craze. I'm not saying it's easy, I'm saying the really, really smart people I know can pull it off. They are the few who could also build something successfully as well, I think. Anyone can build. Building something successful which is profitable and sticks around for ten years or more... that's rare.