There is a very competitive market for colo providers in basically every major metropolitan area in the US, Europe, and Asia. The racks, power, cooling, and network to your machines is generally very robust and clearly documented on how to connect. Deploying servers in house or in a colo is a well understood process with many experts who can help if you don’t have these skills.
Colo offers the ability to ship and deploy and keep latencies down if you're global, but if you're local yes you should just get someone on site and the modern equivalent of a T1 line setup to your premises if you're running "online" services.
