3208's @ 375HP

If you want reliable systems, brand will Be a factor. A big one…. It cost more to engineer and build good systems on a boat.

The big bayliners are fairly good boats but you re still going to have aluminum fuel tanks, ageing gel coat, etc.

why the 48’ limit? For $200k you can find some nice 53 Hatteras with reliable 8V71TIs, fiberglass fuel tanks, solid copper plumbing, better electrical etc some repowered examples may fall in your budget. Much more interior space and storage and very easy to handle thanks to the wide side decks and helm doors.

“Bigger is harder” ? Hell no

my 53 is easier to handle than a 30-40 footer even a twin…. Hell, guess what? The 110 MY I run is easier to handle then my 53….

it s not about LOA. It’s about layout, hull shape, mass and engine torque

Hatt and other mfg's had easy to drop arches, mast and other high items that would drop to make that (#$%%^&*^ing) Chicago bridge. Some of these were rather long in LOA.
There out there, your just finding the wrong stuff lately.

If you are going to keep the boat awhile and put lots of hours on the engines, yes new power may be a great plan to ensure less troubled time down the river.
Rebuilding a later engine may be an idea also. Sadly, you have not mentioned any later engines.

Recovering those funds may / mat-not be realized on your re-sell.
The recreational boat market has been a wild ride these last few years. I expect the same for the next few years.
Remember, it is recreational money, like going to a movie... It is not an investment.

The power choice in a new build may not be of science, engineering or dependability but rather what meets the needs of the hull and cost the hull mfg the lea$t.
Cat makes a heck of a lot of engines. They warehouse them sky high all over the world.
Your a boat builder? 100 engines can be on your door step in a few days.
Back many years (and more), Other than Detroit, what else was competing against the 32xx's? Maybe some Cummins V8s?

So, IMO, it was not the power choice of the consumer, just the economical choice for the boat mfg.

Cat is not and has not built 31 or 32XX engines in a while and parts are getting scarce.

It follows reason when you start with a 150HP engine and start pulling 375 and 450HP from it, life expediency is suddenly shortened.
Cat did make some mods the the later HP blocks (oil galleys), but it was still a poker hand; sometimes you got lucky,,, for a lil longer.

Then, years (years) later, used boat shoppers come along looking at used boats with these old engines. Some puke has changed the oil and spray painted the engine (aerosol overhaul) and their still running. That EOL poker hand has not been called yet.
The drop out used car sales person promises great adventures.
Does that boat shopper really want to play somebody else's poker hand? With near everything against him (her)?

Detroit's have these same limitations. I've just been tinkering on them since I was a kid. I luv the 71's, yet I still hate the 92's.

So my friend, I don't think the market agrees they were good, The market learned to live with them.
As I have learned to live with my 71s.
As most learned that what ever brand daddy's car was, was good also.

The 8.3 was a favorite even before that high pressure pump (Common rail). I don't think there is a more bomb proof engine than the 450HP QSC line.
Of interest; Max HP was 650 but emissions restricted that back to 600HP, not because of any engine problems.

I don't think there are any valve dropping comments around here on the Cummins 8.3.
I can tell you all about Yanmar and Cats dropping valves.