That is just one example. A PSU is just a capital expense and can be sold when you no longer need it for nearly the entire cost. You still must (indirectly) pay for shipping as the manufacturer still needs to ship the miners from where they produce them to wherever they will be hosted. Electric costs vary from place to place so your argument that you pay higher electric costs by running them at your home is invalid.
You can't count on reselling heavy used PSUs for almost full price at all. It's also far easier and cheaper to ship all the miners to one central location than to ship them to individual customers around the world. As for electricity costs, most people do not have electricity costs that are less than 0.1 USD/kWh.
This topic is about cex therefore it should be assumed that he was talking about it. Even if he was not then the overall point of my post is still valid. Mining rewards (net of maintenance) will generally decrease over time as the difficulty increases (although this time around the difficulty will decrease, although not enough to counter the fact that the price of bitcoin has fallen so the net mining reward will still be lower)
It was quite obvious the poster was not talking about CEX but cloud mining in general. Also, that wasn't you point at all. Your point was that cloud mining is unprofitable compared to home mining. That's pretty silly as the maths will show that cloud mining is more profitable for most people.