That 2600K you bought in 2011 was a premium part. The ones you're looking at now are low end. If you look in the same price range you find 6-core Coffee Lake CPUs at 4.4GHz, which has 50% more cache, about 2x the GPU performance, maybe 15% better IPC on typical workloads, and draws about 30% less power under load.

No, it's not the mid 90's anymore where we were tripling performance every time we upgraded. There's still progress.