PCs have other long-term advantages. As noted by @ndalby you can peicemeal upgrade a Tower PC type over the years, incremental changes like faster / larger RAM, faster SSD, faster graphics card, and then replace the motherboard and cpu and then replace the components attached, and ride a sweetspot curver over years, so long as you get a big enough case to handle popular motherboards.
Further the wear+tear components like keyboard where grime and accidents leads to worsening keys is a cheap part, the tower out of the way, mouse similar, and even USB ports can be on a daughter card you can replace.
The issue is the portability.
One way around the portability is to RDP into your desktop from a lightweight lower power cheaper device and remotely control the application which needs high performance. You can port-forward the RDP port. Personally I use a small Raspberry Pi device and do RDP over SSH and forward the SSH port off the router, then all traffic is encrypted.
You can also use Wake on Lan to allow your power hungry PC to go to sleep and you wake it up via a command off the Raspberry Pi.
That portable device can then be sat a Chromebook or lower end Windows 10 device. Chromebook does RDP badly out the box but you can put into Developer Mode then use Crouton to run Linux then rdp client.
A powerful laptop is expensive, doubly so if you drop it and break it, and repairs and upgrades expensive and usually impossible if not immediately then soon.
Typed on an Android tablet to which I can RDP to a Windows VM running Visio and on which I do ffmpeg media recoding.