Rewarding content creation and curation is indeed a $1T idea, I must agree with that. Ironing out the perfect settings to this idea will probably happen with SMT's.
And I really don't know if there will be a Steem-like app on EOS. I don't know if there will be a DEX on EOS. But I do know the capital poured into EOS is pretty formidable. That could mean something about its potential.
But you are absolutely right about the fact that interoperability betweens blockchains is coming. That will change everything!