Remember he was doing this near the turn of the year and needed fast delivery. As he pointed in the video thanks to covid and the way things were in England he wound up paying premium in many cases. And lets not forget the time putting this machine together. More over he gives the prices as they were
at that time throughout the video
As I said if something goes horribly wrong (and boy in his case did it ever) than a PC isn't cheaper especially if you count the downtime, building, and testing as to find out what went wrong.
"Metal is supported by the same AMD cards that OpenCL performs best on and in most cases, when both frameworks are supported,
Metal is the best option" -
2020 GPGPU Roundup: Metal vs. CUDA vs. OpenCL, AMD vs. Nvidia
Watch
Why Apple's M1X Macs Don't Need 64GB of RAM! and understand just how much a game changer the way Apple is doing memory is. Also the price quoted for the M1 was brand new; PC builders have buckets of used parts (some of unknown quality) to work with.
A Refurbished Mac mini Apple M1 Chip with 8‑Core CPU and 8‑Core GPU blinged out to 16GB unified memory; 2TB SSD; Two Thunderbolt / USB 4 ports; Gigabit Ethernet port is
$1,439.00.
If you are smart you will boot up off an external SSD rather than pay Apple's ridiculous premium on SSD and get a 16GB unified memory; 1TB SSD; Two Thunderbolt / USB 4 ports; Gigabit Ethernet port for
$1099.00
And for the Cherry on top the M1 Macmini is doing this all on a
18W TDP plus whatever the monitor and drives may be producing. Heck, Apple has a fan able to cool a 65W TDP CPU in the M1 MacMini. What is the TDP wattage of your "cheap" PC?
Another gauntlet is the
30 W power draw from the wall a fully blinged out M1 MacMini at maximum load. How many watts at full load does the "cheap" PC pull?
When you consider all the factors: initial cost, time saved, RAM efficiency,
and performance per watt the M1 MacMini pounds the crap out of any "cheap" PC which meets
all of those requirements.