The CPC was absolutely not an "impulse buy price point". It was several times the price of a ZX Spectrum, which was a much more "compromised" device than the CPC. Amstrad's marketing trick was to sell an all-in-one, non-toy system at an affordable price that didn't tie up the TV. Put simply, the CPC appealed to the parents who were paying for the computer, not the kids who were badgering for it.
When he says "many devices still required purchasers to undertake their own wiring, and sometimes even solder on their own plug", that's not at all the case. The kit computer in the UK died years earlier with the ZX81. Fitting plugs yourself was not uncommon in the 80s, but no soldering was required.