They will naturally lose some strength, but in my experience, there is a plateau where they no longer lose strength when compressed. I haven't done any measurements or anything, maybe one of our engineering minded Massassians can enlighten us. The thing that really gets you, is dumbasses hear that rumour, and take the springs out and 'exercise' them, by stretching them out. That definitely reduces the strength of the spring.
Anyway, at least in GI mags, the only way a weakened spring is really going to interfere with the functioning is when the magazine gets dirty and the followerdoesn't have the force needed to stay level. Magpul makes really awesome replacement followers that solve 80% of the problems.
Dan, I know I have seen soldiers still using the A2, but it is being phased out by the M16A4 and the M4. I had an M16A2 in boot camp in 2006, but have always had an A4 (or a M249) since then. Actually, I guess I technically had an M16A1 at once point, but it was refurbished and accurized.
Epstein didn't kill himself.