I have a recurring flat problem in my rear tire. I can never find the obvious cause and it does not always occur in the same position on the tube. My rim is a replacement and may be the root cause. I have noted for some time that putting a repaired tube with outer tire back on the rim is ridiculously easy. I do not need tire levers; my fingers will do. Indeed, it practically a finger tip job!
I believe that putting a tire back on my original rim was not so easy; that I really did need a tire lever. But it is so long ago that I am not sure my memory is accurate and that I am not confusing my front and back tire repairs.
So my question to others is simply whether this is plausible and whether most cyclists can expect a little resistance when they try to replace a tire on its rim.