Thanks for the nice comment Dennis, much appreciated. I try and look at things like this logically. So many worry about so much on these rolling Kleenex boxes that I'm surprised they don't have ulcers. I mean, it's not like one is "Investing" in either the motorhome or the tires it rolls and SITS on. Some get many, many years out of their tires, as in say, 8-10 years but may only put say, around 20K to 50K miles on them, plus or minus. And, it's quite possibly they were always parked on concrete.
Some may only get 4-5 years and maybe put the same 20K - 50K miles on them but, they got used more in a shorter amount of time and were subject to the regular wear and tear of our less than perfect American roads but, not parked as much, on ANY surface. So, in short, why worry? They're not going to ROT off the coach in 10 minutes 'cause they're parked on Concrete.
Scott