the primarly reason is because of electricity, if you pay too much for it, it is better to go with cloud site, they aren't very different than mining with your equipments, the scammers are everywhere

buying your phisical equipments does not come without risk, actually there is more, compared to cloud, for example

they could arrive damage(assuming who is ship those is legit)
 
they could arrive in bad conditions and stop working after two week and you can't do nothing at this point

add to this maintanance, better fan system(they are all fuck noisy) ecc...and in the end you will say that it is not worth it to have psysical miners

unless you really love dealing with physical stuff(i love it too, but i love more gpu rig to be honest, sadly they are enarly useless), cloud is more advisable nowadays, the only problem is that only few cloud are legit cloud

besides this cloud work like if you have the best miners in your home, so roi should be around 6 months(assuming no change on the diff)