It's not. There is still well made furniture. Some manufacturers still produce quality frames and cover with quality fabrics, BUT you'll have to pay top dollar for it. "Disposable furniture" is a product that is made and sold with planned obsolescence. Have you ever seen the dumpster area at college move out time? Start with this thought, "when we get there we'll buy a new sofa, so we'll just throw this one out and then we don't have to move it." But it's less than 7 years old. It's barely dirty. A disposable sofa is $600.00 a quality sofa might be $4500.00. And that's the low end of a heritage piece that can be passed down through generations. That is worth recovering. Recovering runs about $1200. Probably 90% of the shoppers choose disposable furniture. Same thing with mattresses. One of the concerns is the petrochemicals that are going into the landfills with people throwing away mattresses and furniture rather than move them. There is a niche market that is growing for 100% all natural product furniture. Find a knowledgeable furniture marketer and they will direct you to a quality manufacturer.

TL/DR You get what you pay for.