No. If I had 50.1% of all the steem on the market, I could project my own will onto everybody else.

You were wrong even this time.
https://steemit.com/eos/@dan/in-defense-of-consortium-blockchains

However, as far as war against spam is concerned, much less than 50% of all STEEM in existence can suffice.

I believe in the right to free speech and thus cannot stop the spammers from spamming.

And this is why I believe STEEM will not last until 2024.
A recent discussion I found can make it last longer, but in the end it is still not scalable to FB dimensions even if for this reason alone.

But if I publish really good content, I'd attract more viewers – and people would move away from the spam posts, and upvote them less. If I resteem other good content, then more people will read that to. By becoming known as a publisher, and resteemer of good content I can deny the spammers.

Another example of extreme naivety and cluelessness.
Spammers need no authentic people's votes, their mastery of bidbots fueled and reinforced by self votes are enough to let them grow.