> IKEA also refuse to sell you spare parts.

Sorry to call bullshit but I think that’s exactly what this statement is.

Just looking at our wardrobe and thinking about how it’s actually not one thing at all, but made up of dozens of different SKUs, and how I could reorder any of them individually if I needed. There are also third party sellers of parts such as runners, door rails, and the like (not that you need them since these can all be purchased from IKEA anyway).

The challenge with IKEA is colours: they used to offer more colours, but now lots of stuff is black white, grey, or beige with no other options (and sometimes white is the only option). If you need to replace a part in a colour other than that nowadays, you’ll perhaps find it difficult to impossible.

Depends on the specific piece of furniture, and how well you treat it. I have had quite mixed experience. Its not going to last like expensive stuff, but its generally far from the worst.

Quite a long comment to write that you've never once seen ikea furniture.