Earlier quoted context omitted.
Does the tool degrade gradually over time or is it sudden? If the former, you're much better off over the 10 year span with the high quality tool, because the time you spend dealing with its degraded performance is much less. IME it's almost always better to go for a high quality, old, used tool than to buy a low quality new one. Usually the wear parts are replaceable or rebuildable as well.
Your comment is just nit picking. Point was there's a lot of situations where the math hugely favors the cheap tool. Used tools of the brands that anyone screeching about nice tools would consider to be of repute are going to generally be priced at equivalent to new tools of unknown brand. Specialty tools frequently aren't available on the used market. Anything that spins or plugs into the wall tends to be finicky af…
I guess all that is to say in my experience the cheap crap breaks and ends up being more expensive either in opportunity cost or cost of replacement/modification.