...and ask AA to offer all its customers to rebuy or reinstate expired miles at an attractive price or rate.
They do this already. It's just that you don't think it's an attractive price whereas AA think it is,
And look at the big competitor airlines of AA in the market: United Airlines and Delta Air Lines frequent flyer miles do never exipre.
AA does not have to do what the other airlines do. For example BA miles expire after 3 years. AA could do that as well. But they don't
...it was the athmosphere of uncertainty in general that kept us away from using AA miles. All solution oriented answers and ideas are welcome and highly appreciated.
There were plenty of solutions that would have extended your miles. The simplest would have just being buying the minimum number. And IIRC donating a small amount to charity would also have extended the miles
BUT you are aware that AA miles expire because you asked about it in October 2019
https://www.flyertalk.com/forum/31592103-post1613.html