I disagree - I've been requesting this on-and-off for years.
In the same way I passively pay Netflix to be able to stream movies, I'm happy to passively pay Twitter each month for the flow of conversation if it allows them to exist in the long-run, and get better.
If its viable for them to charge me $7 to $10 a month so I get an ad-free experience and they can wean off ads as main revenue source, then great. Sign me up.