A not insignificant amount of US foreign policy is driven by the fear of looking "weak" to the US public. Look at the withdrawal from Afghanistan, and how that dropped Biden's approval numbers. One major contributing factor to getting Reagan elected was Carter doing the right thing and handing over the canal to Panama. And the Vietnam war definitely went on as long as it did in part because every president back to Kennedy thought it would be political suicide to just "give up".

With Cuba, any olive branch a politician tries to extend gets painted as being soft on "dictators". Bernie got flak for speaking positively about Cuba. Karen Bass did too. Obama tried to open up relations more (maybe, I've also heard he just parroted the company line about how Cuba needs to become capitalist before the US will have a relationship with them) and also got raked over the coals. Politicians will not try and change status quo with Cuba because there's no incentive too.

At some point though, it would be useful to discuss the US public's role in empire and how we think anything less than pushing everyone's nose in the dirt is "weak".