Here is a “top of mind” list of air-spaced telescopes that all had serious lens centering issues
Meade ED apos from the 1990s
Takahashi first run TOAs
Synta first run 150mm ED doublets
In each case, if someone had an issue the scopes had to go back and if they didn’t have an issue the odds are that they would down the road. The cells had to be redesigned or a Band-Aid fix applied.
In some cases, even the fix was problematic, as with the Meade doublets and in “some cases” never corrected to the customer’s satisfaction. This does not count mold issues or dirt between the lens elements that can happen with air-spaced lenses.
It is true that we do not have an exact percentage of the oil-spaced issues but even if you count the number of issues in that CN thread, when compared to the number of scopes that have been produced over the last 40-years, the percentage is low. And the fix is easy compared to an air-spaced cell that needs a cell redesign or the addition of centering screws or trying to correct a mold issue.
I’ve owned air and oil-spaced objectives for over 30-years and never had an issue with either. Just get the scope you want and take care of it.
I did have a neighbor’s cat jump into my 15” Dobsonian and scratch my primary mirror and I had to send the mirror back.
So sometimes stuff happens, even to reflectors.