That future is already here. Lightweight end user devices and data centers are the present day of computing. High-end laptops and desktops are only useful for niche tasks such as AAA gaming and some forms of software development and video editing. If you need performance, it's usually more convenient to have it in a data center than on your desk.
The main advantage of the M1 is the power consumption, not the performance. The current devices are already fast enough for most tasks, but people do appreciate longer battery life and silent operation. For some time now, end user device lifespans have depended more on durability than performance. If you bought a high-end laptop or desktop 10 years ago, the device is still fast enough for daily use, but the hardware is probably no longer in a good condition. If nothing else, thermal paste has deteriorated over the years, forcing fans to run faster and the CPU/GPU to throttle down sooner than before.