Not sure if I just got unlucky but I’ve owned about 8 outboard models and bought my first sterndrive last year.
its been an absolute nightmare. Every old part broke and every new replacement part broke.
I’m exclusively outboards only now.
Not that I want to turn it into a debate or anything but I don't think that's typical. I have been running my old double eagle for 6? years now, including when I lived on Ruxton Island and had to commute to Duncan every single day. That boat sat in the water for about six months; the only time it was out was when I beached it at high tide to scrape the bottom. It ran morning and night, Monday to Friday at least, for months. Before that it was a commercial transport for a dock builder and ran...a lot. I have full maintenance records from the dock builder, and they're thorough, but not tons of parts replacement, to be honest.
At the beginning of 2019 before I moved to Ruxton, I had to get the heat exchanger welded because I'd left water in it and it froze.
At the end of the year, I had to replace the U-joints. But they had god knows how many hours on them and they were fine, just creaky.
What else...cap and rotor at the beginning of the year, and clean up the engine ground a couple of times. Zincs.
That might be the whole list. Oh, wait, no, the starter died in the winter of 2019, again with god knows how many uses on it, it was ancient. But you get the idea. I'm not trying to say they're better or even the equal of a modern outboard but that's a forty year old Volvo leg, bolted to a PCM 302 that's maybe fifteen years old.
I'm not an advocate for I/Os or anything, but I don't think your experience is typical, although I don't dispute that it definitely sucks and in the same literal boat, I'd also probably never touch another I/O.