Well, his argument is not about the number of chips but rather component origins. If you are about to pretend that you are in the 80s and you develop a computer in that time, you've got to use what was available. I argue that ZX Spectrum used custom-made ULA and you kind of emulate that approach to design with ATMEGA and he just laughs :)
The truth is that we live in magnificent times where there's a wide range of choice on how to do things and it is amazing.
The ZX80 used 21 (IIRC) off-the-shelf TTL chips.