> at least allows for the possibility of diversity of opinion. Left and Right can both choose to pay.

This has multiple issues.

The older set up was not there to promote visibility but to provide a layer of authentification, most blue ticks were brands and recognisable people. Now its mostly scams, allowing anyone, especially potentially malicious actors, to don the mask of credibility is not "allowing the possibility of diversity of opinion" is allowing the fox in the hen house.

Secondly, if you imagine the goals of right wing people to maintain current power structures, and the left to disrupt them, then the ability to pay is already corrupted due to the current power structure being supremely lobsided. Aka those with all the money are effectively the only ones who can pay. (In law this is called 'right without a remedy', its when you technically have a right on paper but could never actually exercise it)

This whole situation also enables a problem we already know exists which are state actors. Russia was part of a disinfo campaign through FB tools in 2016 through cambridge analytica, and used bots in twitter in 2016 and 2020 through multiple state sponsored bot farms. Allowing that kind of state warfare to be amplified by spending money is really really poor choice from a platform prespective. Without those tools, organic growth is harder to achieve and getting around bot detection tools means a part of the infra would be caught before it caused damage (even under those circumstances, there was plenty of damage done). Removing all guardrails is a frankly indefensible choice in terms of public safety