Chainsaw Repair

I have worked on small engines for over fifty years, and I have seen a lot of changes.
The last chainsaw that I bought new, was a 1980 Husqvarna 40. I wore out three bars and countless chains and rebuilt the carburetor two or three times. It still runs like new and engine hasn't been into.
The point I am trying to discuss is the fact that I never had to periodically adjust the carburetor. Each time I rebuilt/cleaned the carb, I would just return the screws to where they were.
I found this to be true with lawnmowers as well.
With any of todays saws, even a change in brands of gasoline or oil will likely change the carb settings.
I am referring to muffler and carb modded saws and other small engines, but more so with chainsaws.
Do any of you have the same memories and why do you think we have to really watch carb settings today?

I should have mentioned that I have adjusted the carb many times on the 40, in the last few years.
I think it is in the quality of the gasoline we get today. Just wanted some other opinions.
Old Craftsman (roper) 3.7 I bought new in about 1980, would barely run until I adjusted the carb, then ran excellent.
It had been stored dry for over eight years.

I am sure the fuel has some to do with it. The additives chance from winter to summer I believe and you never can really tell the ethanol content, even if supposedly E0. Along with that I also would guess with manufacturing tolerances much tighter than in years past that things like carb adjustments are probably a lot more precise than older models which could make them more sensitive to variations. My guess anyway.