I've never had problems with IKEA stuff falling apart or getting crappy, even with heavy everyday use.
I do LOL at people who think they need $4k Herman Miller chairs, etc. Talk about a colossal waste of money.
I do LOL at people who spend 1k/year on mobile phone service (iPhone). For three years of smartphone service you could have a timeless couch. I don't mind spending 1k on a pendulum lamp, 4k on a chair and 6k on a sofa because they'll last forever.
However, I also have a 20 phone, no car, and a 300 32in LCD TV:
It's about priorities. The furniture lasts a lifetime, never loses value, and gets passed to the kids, where it STILL looks good 30 years later.
As far as IKEA goes, their STOCKHOLM line is great value for money. They usually have a 15-year warranty but aren't cheap (why people usually go to IKEA). I would expect around 1000-1500 for IKEA STOCKHOLM 2-seater sofa and I would epxctit to last for 10-year of heavy family usage.
The cheap stuff is cheap.
Also check out the LC2 chair and the LC4 lounge (non-IKEA), they're worth looking into for lifetime furniture. Also, I'd stay away from replicas, the quality is lower and the cost is high