Thanks for your questions;
I too have no idea about the effects of alcohol on bag wear and I agree with AlexT about a possible reason for less wear time. However, there are many more possibilities in this regard which have been discussed by different folk on here in the past.
Manufacturers are often experimenting with different material's and adhesives, which, from one perspective we should be grateful for because it means that they may be seeking to improve our experiences and the functionality of their product. From another, more cynical perspective, they may be following the profit motive and making goods that don't last quite as long, a strategy which potentially makes them greater profits.
Recently, Hollister discontinued their line in adhesive spray 7730 and when I enquired as to the reasons why, I was given the impression that it was no longer relevant/'profitable' for them to produce/market it. Hence, my reference to the second optional perspective.
There are many options available from other manufacturers and they are often wiling to tempt you towards their products by sending free samples, so why not try a few others to see how you get on.
I gave up with with manufacturer's baseplates that either did not stick efficiently or stuck so well that they were difficult to remove. So I took to making my own baseplates, to suit my own particular needs. I can stick manufactured devices to my baseplates and they last for months.
Here's hoping you can find something to suit your own needs soon.