I used to think this too, but e.g. Bosch and IKEA have great replacement parts websites accessible to the consumer. IKEA’s parts are mostly free, too! With modern logistics (automated warehouses, cheap shipping, ordering online) it is actually a solvable problem, if the company gives a damn about it.
I'll take that as a recommendation, thank you! Fwiw, i have found spares for many brands by searching model numbers and wading through spate parts aggregators. The market exists. It's often uneconomic :-(