I think you're mostly right (or at least insightful), but there's a caveat. Decentralization can't create big companies, by definition, but it can destroy big companies.

There's ample historical examples of that. The Internet (originally) built upon the plain old telephone network, but eventually ended up supplanting telephones, AOL, the big-3 TV networks, and many other communication monopolies. Open-source software has commoditized many formerly-profitable software businesses. Napster and the P2P craze failed as businesses, but not before taking down the record industry and opening the door for iTunes & Spotify.

For many of crypto's proponents, that's a win. They'd be happy if a bunch of banks & VC firms faded into obscurity. There'll be new evil corporations built on the backs of crypto (just witness the community blowback against Coinbase), and in the long term some form of centralized power will just colonize the crypto space the way Google & Facebook colonized the Internet, but in the meantime it may shake up quite a few old industries.