The first thing is the electricity rate if you have high electricity costs and own mining equipment you won't make any profit you won't make any profit because mining machines are power-hungry.
And the 2nd thing is people do not want to maintain them because they don't want much hassle maintaining them due to a lack of knowledge.
And there are lots of factors why people choose to buy hash rate than owning a miner like scalability and risk management, etc.
If cloud mining is so good, then why don't mining equipment owners sell their rigs and invest in cloud mining? Why does someone come up with an idea to buy an equipment and do all the time-consuming job to offer hashrate with profitable terms to someone in the name of cloud mining?
Imagine, you buy a mining equipment and host them in datacenter, are taking care of things and manage your mining rigs. Why will you rent your hashrate to someone else and at the same time tell him that he will profit this way? Won't it be beneficial to just join the pool and mine on your?
There are so many benefits listed in favor of cloud mining, it looks questionable why would someone provide a rig for cloud mining.