In some cases, that’s true, but sometimes you need to update cutting rules because of law changes, or you saw different way of cutting for example. There are cases where this is not one time investment. What I agree with that cutting-it-yourself became significantly cheaper

It's more like he was renting a knife to cut fruit for some reason and now, and instead of just buying a knife, he built one from scratch.

(1) Let's hope he doesn't cut himself if the knife breaks apart while in use.

(2) Why is it so hard to just buy knives these days? Why does every knife maker suddenly feel entitled to charge rent?

I'm all for DIY instead of hiring others, but the insanity here is the rent vs. buy thing going on in the industry.