Agreed, these views do not reflect reality but appeal to people's ideals. Chasing ideals is what gets us into trouble as a society. If somebody comes up with a better STEEM platform, it's going to be to compete with the others for eyeballs. Competition drives innovation.
If Steemit.com eventually dies, it's because they couldn't compete for user time with the other platforms. That being said, it's not a zero sum game, so there is no reason there can't be cooperation and competition at the same time as you implied. It reminds me of when the BTC Core dev found a BCH bug. He didn't have to let them know, but he did.