There's a great Dr. Seuss book called "The Sneetches" I think would help you to understand what's about to happen.

Blue checkmarks will be people paying to market to you. It won't take long to block people with blue checkmarks. Before it was some verification that this was a real person/official entity. As for twitter becoming open to more "diversity of thought" I mean, I guess if you want more ads, sure?

Twitter devolving into 4chan or as you say "diversity of thought" will not lend itself to having journalists wanting to keep their status on the site.

"as Twitter becomes open to more diversity of thought."

That remains to be seen. It might as well just lead to a shift of thought. Or that all opinions are welcome, but only those get traction and an audience, that happen to align to the opinions of Musk (and whoever else, who has invested heavily behind the scenes)

I use Twitter more than I should - though in a read-only context - and I don't understand what "diversity of thought" is missing at the moment. You can go on any leftist's Twitter and see replies calling them communist, calling trans people mentally ill, etc. The only stuff getting banned consistently is either incitement, like calling for "death con 3" on a group of people or outright racial/gendered slurs. There are mass-reporting campaigns (targeting individuals from both "sides"), but these are usually overturned and are not entirely Twitter's fault. Sure, better moderation would improve the outcome in mass-reporting cases, but it's less a case of bad policy and more a case of Twitter needing to invest more in moderation. Something I think is less likely now that Twitter is loaded up with debt.

Apparently there are about 400,000 currently verified users. So, assuming 100% buy in (or enough people buying the blue check mark that it makes up for those who don't), that brings the total revenue from this scheme to ~$100M a year, or about 2% of Twitter's current $5B annual revenue.