I completely hear you and am so empathetic when reading your post. That sounds nearly identical to what I've been through this past year-- right down to losing ALL confidence in dragging the thing clear to Lake Powell and having it fail. TWO failed trips last summer (electrical failure - wouldn't start, and then pulley's failing the next week) and then the shaft drilling a hole in the gas tank a few weeks ago on our first day there (actually ALL incidents were the first day every time :-/ )..
That said, I'm not really sure what MY advice would be. As several others have pointed-out in this thread alone, all boats have issues and it's luck of the draw. I've also had several business associates and friends over the past few months reminding me of this very point. However, given so many of the "common" issues and compounded or 'severity' of the issues that we've had with Centurion, it simply HAS to be create a sense of bias and an argument AGAINST when considering a Centurion again. And, clearly, in the 3-4 years since your boat was built, the QC issues continue-- consistent or not, they're there.
I've got two close friends with Nautiques and two with Malibu 23LSV's. One of the Nautiques (a 2018) had total engine failure on the second time out and had to have them replace the engine entirely. The others have all just had minor issues like throttle (by wire) linkage issues and various small hinge or interior problems. So I DO agree that all boats are just made with a different sense of QC than a car (given the fact that there are so many less moving parts that it's simply ironic). I also know of (not personally) a couple people with 2017 Ri257's like mine who've only had a couple of the issues I've had which were quickly resolved and they're completely happy since purchase. Also know of a guy with a new Mastercraft X46 who's had no issues since purchase last spring.
I guess it really boils down to which roulette table you wanna roll your dice on. As I said early-on (a few weeks ago) in this thread, the lay-out, size, and functionality of the Ri257 has me hooked-enough that I'm gonna put my faith in this new '19 I ordered and hope I have a good experience moving forward. None of my buddies' boats really impress me (size, gas mileage, layout, or functionality) quite as much as mine has. However, another year (2017 & 2018) like I've had without even feeling confident in taking a group out for an entire day and I'll never utter the word Centurion again.
Bottom line-- it's a toss up. Sorry about your experience. If it's been anything like mine, the expense of boat ownership didn't even come CLOSE to non-ownership.