Really, it depends on how you use it.
A Desktop used in a very rough way may not last long, but a laptop taken good care of may last long. It also comes doen to how lucky you are.
Yeah, generally Desktops will have longer lifespans, are cheaper, more powerful and also a lot cooler due to all the cooling options and also you can upgrade the parts as you wish.
Also, there is not a single laptop powerful enough to compete with the highest end, and even high end desktops.
If you have the space, a Desktop is always recommended for a better gaming experience. If you don't have the space, then surely, a laptop will be better suited for you.
And, USAFret +1 Lol