I agree with you. Steemit is not a social media site by anyone's stretch of the imagination. It's a blogging platform only and has always been that.
The majority of people on Facebook, Twitter, etc., could care less about making money online and would never want to spend time on a platform where most of the popular posts are about the platform itself.
The people who do arrive here and stay are here primarily to make money. Giving large businesses top exposure will just knock the little guys further down. It may raise the value of Steem, but if the little guys are making no Steem/SBD, it won't matter much to them.
Steemit must eventually become simply a central portal. Other and better platforms with their own SMTs are the future of STEEM and will fuel adoption of the token more and more.
DTube, as an example, will have it's own SMT when ready, and that will likely become a more largely adopted platform than Steemit itself. Others will arise and evolve. Some will fail, but some will thrive and eclipse Steemit.com in terms of "active" users. Steemit itself will grow, but as the gateway and central portal to everything else.
I think you've made some good points here, @joanaltres