Why Don't More Run A Server Room Instead of Renting?

GOB

I see some businesses run a server room instead of colocation or servers in a public datacenter

its so simple, they are just using a little room, and using 1/2 PK air conditioner

I dont know how good their servers or Networks are, but their websites looks fast enough & have already been running for a few years.

what is your experience about this? Especially concerning the network/internet access