Conventional toasters are so cheap it makes no sense to try to repair them. Plus they aren't built to be repaired at all. When my last one died I tried taking it apart to see what went wrong (element burned through as it turned out) and see if I could fix it, but the whole mechanism was basically as single piece put together with spot welds and rivets, and with part markup being at least 2x or 3x initial cost there would be no way repairing it would make sense. I could gripe about it being cheap junk designed to fail, but it lasted over 20 years and browned thousands of slices of bread.
If some well built toaster that won't fail costs more than 4 times what the cheap toaster does, then it probably doesn't make sense to buy it. Especially if you can't guarantee that the well built toaster will actually last a lifetime.
If it cost only 4 times as much I'd probably consider it, but 10+ is just a really hard sell unfortunately. I had to scrap a perfectly good toaster because I couldn't find a replacement for a cracked plastic part that is supposed to make or break contact in a switch and engage the electromagnet. It would still toast fine if you held down the lever, and it pained me to toss it, but I couldn't source or fabricate a safe replacement part.
I'm sure the manufacturer(s) don't want to worry about self-service causing house fires though, and it costs a lot to create, maintain, and distribute a stock of replacement parts for what ultimately is a disposable appliance. I just wish I could find a solid basic consumer/prosumer toaster in the sub-$100 range.
Replacing tiny broken plastic parts is the main reason I now own a 3D printer. Granted, a toaster is one of those places where the relatively low melting point of PLA or PETG might be an issue, but it is still very useful to be able to fabricate replacement parts that are otherwise impossible to find.
Even better is how I can redesign the replacement part so it doesn't fail in the same way next time.
In theory you want anything with a finite lifespan to not need any repairs or maintenance during its lifespan and only fail once its lifespan has been exceeded.
Repairing isn't supposed to make sense, you get the next, better iteration of the product.
In practice, products fail way too early and for easily avoidable reasons justifying the need for repairs.
If some well built toaster that won't fail costs more than 4 times what the cheap toaster does, then it probably doesn't make sense to buy it. Especially if you can't guarantee that the well built toaster will actually last a lifetime.