Great for a year, lumpy after that

I have owned this mattress for over three years; my wife and I are height weight proportional and in good shape. Took at least 6 months to break in and then seemed like a great bed. Unfortunately after that it continued to break in more and developed indentations and a hump in the middle appeared. The base support of this mattress seems great, no squeaks and minimal motion transfer, but the top comfort layer is very poor quality and this bed needs to be replaced. I'm basically done with Serta, Simmons, and Sealy. In my opinion these "traditional" mattress companies business model is to milk their existing brand appeal until the newer companies and business models eat them up. Selling a quality product is not part of their plan.