A few years ago I recommended to my company that we move off of cloud and co-locate into 2 data centers (Dallas + London). The dallas colo cost us about $200 per month (4 U) and the London colo cost us about $400 per month (12 U), for a total hosting bill of $600 per month.

We purchased a total of 8 used HP servers averaging about $1000 each fully kitted ($8K). So total 3 year cost is about $30K

This compares to $2500 per month doing AWS. Yes, we have to manage the boxes, but for 1/3rd the price its really not bad.

By far the biggest gain is we probably have a 5x compute gain - we run dozens of VMs and many dozens of containerized apps on our infrastructure.