Personally, I think folks are correct when they say that when Castro is gone it won't take long to normalize relations.
As to some of the other points... one thing I seldom see mentioned is that in the Fifties, there were a lot of people in the United States who didn't particularly care for Fulgencio Bautista and/or the sugar companies. We didn't get a new car in 1958, and my mother was pretty hacked about it; Dad responded to a plea for support instead.
I well remember sitting in front of the TV when the clip was played where Fidel declared that he was a Communist, and had always been a Communist. We were visiting friends in Stephenville, and the look Dad and Jimmy exchanged on hearing that had to be seen to be believed.
That's where Jesse Helms's basic support has always come from: people, mainly in the South, who supported Castro against the vile bastards who were running the country -- and felt flatly betrayed when the Bearded One declared for the Other Side, who were at that time quite truthfully regarded as being Out to Get Us.
Most of those folks are old, now, as Jesse is, and when they're gone, the only support the anti-Castro people will have is from the likes of Bacardi. When Fidel finally dies, too, there'll be no object to focus on. Reasonably normal relations will follow fairly quickly (a couple of years, minimum; definitely not overnight).
From the business point of view, yes, many other countries have nationalized U.S. corporations' assets and not been penalized as Cuba has. OTOH none of them has done so as completely and sweepingly as Cuba did. The United States doesn't automatically compensate companies who've been seized, but the end result is the same as if they had -- U.S. taxpayers wind up paying. I personally have precisely zero sympathy for the sugar companies, who were running their operations with what amounted to slave labor; but there were a number of corporations who were just doing maquiladora-type things, and Bacardi, despite its legal location here, is and has always been and Islands company. They got gutted simply because of a legal fiction about where they were incorporated, and are rightfully sore about it. If Castro had satisfied himself with seizing the sugar companies and the land they owned, and the assets of Bautista and his cronies, and left the rest alone... lots of people, including Dad and his friends, would've snorted and said, "Yay! Go for it!" And that would probably have included Jesse Helms.
There is no way the Cuban Revolution can continue absent Castro. There simply aren't any charismatic people around to take over, and the ones who are publicly known are regarded as precisely what they are -- apparatchiks. Socialism is, in its final analysis, just feudalism with the serial numbers filed off; regardless of official titles, the man is and has always been Fidel I Castro, Prince of Cuba, Scourge of the Windward Passage, and Protector of the Meek. Unfortunately he doesn't have a son to invest with primogeniture, and there isn't any other way for him to pass the power he holds. So when Castro dies, there will be a period of great turbulence. The one thing we here in the U.S. need to do when that happens is to try hard to keep the South Florida Cuban exiles from pulling the same trick the West Germans did when the wall came down. If we get a flood of people heading over to explain to the poor benighted Cubans that they've been doing it wrong for forty years and their betters will be happy to take over and show them the right way... it could get nasty.
And Ashton -- in many ways I share some of your attitudes, but don't let your bitterness get the better of you. Our Good Friends the Canadians, who consider it fun and appropriate to tweak the eagle's tail whenever possible, report to me that the real live Cubans are anxious, even avid, to take up the professions of waiter and the like for the sizeable resorts and playgrounds established by European countries for tourism in Cuba, largely by Our Better Friends the Associates of Michael Merlin. Whether the actual result is pretty or not, people do tend for some reason to gravitate to where they can actually make money, eat, live in reasonable housing, and other unreasonable, resource-confusing things.