It's mostly the modern graphics cards that are consuming power -- which makes sense, really, since they're "computers" all to themselves with massively parallel CPUs.

I run a 650W power supply in a fairly beefy "gaming" PC I built for flightsims and other things. That's more than enough to run the overclocked CPU, liquid cooler, and mechanical hard drives. I could use a lower-rated PSU, except that I also want to run a modern graphics card, and that's what can push the power consumption up when it kicks into high gear.

I have a "gaming" laptop that uses a full GTX1060 graphics chipset (not the reduced-power "Max-Q" series) that gets by with a 180W brick. It's CPU isn't as fast as the one in the desktop, though, and it uses a combination of SSD and hybrid SSD-mechanical hard drives for lower power consumption. It's probably possible to build a full-feature "gaming" computer by carefully choosing components; it's been done in micro-ATX and mini-ITX form factors -- they can get away with 500W or less power supplies by carefully choosing the outboard components and by sticking with CPU's that might not be the ultimate speed champions but are still fast enough to do heavy lifting. It's just not necessarily a big area for mass-marketing.