Before disposable stuff, people bought used furniture and then re-sold it when they moved. It was less convenient, but certainly not 2-3 times more expensive, since good furniture holds its value.
Most of the times when you rent you don't have the actual time to sell the furniture that you bought, because the "finding a new place and moving right in"-period is pretty short. Plus, you kind of need your bed, your chairs and your table until the day when you're actually moving out, so if you were the one who had actually bought them and there's not enough space for them in the new place then your only solution is to leave them behind.
- Finding a buyer (individual or store) and arranging with them to pick it up on the day you're moving out
- Selling your stuff a few days before leaving and improvising temporary alternatives (e.g. $20 air mattress on the floor, or staying with friends)
Note: I'm not saying these are better than just writing off your current furniture and buying new stuff. All I'm saying is that other options existed before IKEA, and continue to exist today.
