Well I suppose it’s a case by case situation. If it happened to me, 100% I’d buy another brand for my next laptop as I need something reliable. Being repairable/upgradable is not an excuse but should be an improvement over other brands.
But to put things in perspective, if I’d stop buying for this reason, I’m pretty sure it would be because of bad personal experience, more than real unbiased reasons. First, I do not expect mainstream brands to provide a good service over warranty, I’d even say I expect from them to do not provide any help at all, except maybe Apple sometimes. Second, at least your laptop is not a piece of junk as you can still buy another motherboard in the same laptop case. And third, laptop failures of almost all brands over few years used to be pretty high (like 15-20% over 3 years or something like that), so even if you’d always been lucky (like me), you should not think that laptops other than framework rarely fails because it’s definitely not true.
But I get your frustration and I’d be so annoyed having been provided two failing motherboards.
Maybe that would be interesting to have some transparency about failure rate.