Your logic is impeccable!
For what it’s worth I was questioning the apparent contradiction between the post “...the payload was likely lost for good” and that the balloon apparently came down in 48 feet of water.
And I understand that rough seas are hampering the recovery of the payload. I have to think that recovery of an object at a depth, even one the ‘size of a bus’ is well within the capability of our Navy divers.
But do you look forward to learning from the government what this balloon was actually doing?
It's essential that the sunk payload be recovered quickly as saltwater is corrosive to electronics if not adequately protected. Just guessing, I suspect that the whole payload would be disconnected from power sources likely while still in the water. Once recovered to the ship, probably start a fresh water rinse before anything else is done. Pull circuit boards out fast.
I think the key items to exploit are likely microprocessors and memory. Most everything else is simply a support function to keep these two items functioning.
I've read speculation that self destruct systems may be present. No clue if this is accurate.
Navy divers can work okay in rough seas but past a point, payload recovery to a ships deck gets more complicated to impossible. If necessary, the divers can work off of RIBs which bob like a cork. Underwater, it's pretty calm water although currents can be present in shallower water.
Professional diving can be incredibly dangerous. One of my cousins was married to a North Sea diver working in the oild fields when her family lived in Scotland. After a couple of years, they moved to the US and the guy took a contractor job doing nuclear power plant maintenance. He only worked a month or two then would have his yearly dose of radiation. Vacation a year then back to work. This was way safer than the North Sea pipelines and rigs.
My opinions…