I don't doubt you've had trouble, and I don't know what their website or otherwise remote customer service is like, but to say that the service is just not available at all in the US appears incorrect.

Assuming there is a store nearby and even that the company is still in business. It's vendor lock-in.

Meanwhile, my solid wood sideboard could be repaired by any competent cabinet maker, without needing specialist hinges or plastic brackets. Not that it is liable to fall apart as easily as particleboard & veneer.

IKEA can be repaired by any competent cabinet maker. IKEA doesn't use anything fancy and weird, all their stuff is standard or a slightly variation of standard and could easily be replaced by a standard one. In fact most of the IKEA stuff is so popular it has become standard.

IKEA sells both particleboard & veneer for their cheap/budget friendly stuff and hard pine/other wood for more expensive stuff.

You can't have cheap and solid wood, it's just too expensive.

Go down to the local wood shop and buy all the wood you need to make a sideboard and tell me how much it will cost. Certainly will be leagues higher then buying a particleboard & veneer version of the same thing.

Pine is a softwood.

Any novice woodworker/joiner should be able to fix IKEA w/o any parts from IKEA even.