I bought a HP All in One, 27", i7, 16GB RAM almost 4 years ago at Costco for $1200.
Luckily, I bought the warranty and I was recently reimbursed when it stopped working.
That same machine is now $1100 at Costco. Why aren't the computers getting faster / cheaper anymore?
They're getting cheaper, but there's really nothing to improve any more.
My computer that cost me $700 to put together, is 9 years old. I've replaced the HDD and the power supply. I use it still for work. It's an core i7 with 8 cores. I expect to use it for at least 5 more years.
There are minor improvements in the CPU, but really what do you want out of a computer today?