What in particular are you referring to that could have been designed on CAD in 15 minutes here?
Normally, whenever I have seen an Abom79 video doing something, it was some big-ass part that they were doing manually because either:
A) they were refurbishing something so they had to kind of cope with any non-idealities that arose
B) the part was very simple but was just a really big-ass part that really didn't fit well on anything so that had to kind of make it up as they went along.
Of course, it could just be that I don't really watch Abom79 videos unless it's about some big-ass part, so I could very well be biased.