You know, the downsides you mention are the primary reason I haven't bought a drysuit. My wetsuit is adequate. I don't like it but it is adequate.
If you're diving in water below about 70* (which covers an amazing number of dive spots in the world) then a wet suit is simply not comparable. If what you're talking about is about your top-side comfort and bottom time, then a wet suit is not adequate. It's just not. Sure you can get in the water, but I totally fail to see how being forced to halve your bottom time for the day compared to dry suit diving due to showing early signs of hypothermia constitutes 'adequate.'
The whole idea of turning upside down (and, yes, I know how to recover - at least in theory) just has me thinking the whole drysuit idea just isn't worth the hassle. Huge air bubbles migrating all over the place...
I had to do that exercise for my dry suit class. I had to work pretty hard to manage to actually achieve that position. I dive dry almost exclusively, and frankly, I can't imagine getting inverted without trying to do it. It simply doesn't happen if you have spent the time to work out buoyancy and trim.
The only time you get "huge air bubbles" moving around is if you are trying to ignore the purpose of your BC and are over-weighted. Otherwise, you put in enough air to alleviate the squeeze, and have a great, warm dive.
Now I have another inflator hose, a dump valve to position, put in enough air to eliminate the squeeze, be sure to vent the air before rocketing to the surface, diddle with the air in the wing, carry even more ballast... All this seems like just too much effort.
The one point you almost make that is valid is the need for more weight can make be a big pain on the surface. I admit it, when walking down the stairs I'd rather be carrying 9 or 10# less led to be diving wet rather than dry. But that is a concern that is eliminated in the water.
It's clear that drysuit users like them. If I spent that much money, I would claim to like them too!
Sorry, no. We're not just a bunch of self-deluded buffoons engaged in justifying our purchases to ease our troubled minds about the money we wasted. Diving dry, once you're trained and have gotten used to how the dry suit operates and feels (which is different than a wet-suit, to be sure) is a superior experience.
But I KNOW I like diving in warm water. I can't come up with one good thing to say about diving in cold water other than "well, it's diving, kind of".
Again, if you've never been on an ice diving outing with a couple of dozen divers, you've missed one of the greatest diving experiences there is -- both above and below the water.
Some of the greatest sights in the world are in cold water -- both fresh and salt, and you're missing all of them if you only limit yourself to warm salt water.
Take the vacation. Drysuits will always be around.
While it may be the right decision for the OP to choose a vacation over dry suits, that decision should be made balancing realistic assessments of the costs and benefits of each choice. The folks advocating dry suits here, far from being deluded as you suggest, are stating that dive time in general, comfort and the ability to dive year round outweigh (in our views) the benefits of a week or two someplace warm.
When I was last in the Caribbean, I averaged just above 4 dives a day for my 7 day stay -- 31 1-tank dives.
I can easily do 6 1-tank dives a month around here without stretching myself very much. That means I'll dive just as much over the course of one fall and winter as I would on that vacation. And I'll get to see stuff I'd never get to see simply doing warm water diving