Springfield Armory Receivers are the gold standard on the commercial market. They stand behind their product , at least in my experience. I have one M1a that is on its third barrel, another on its second. There is no reason to assume that your M1a is any better or worse than mine.
Parts will wear out, parts wear out on all machines, you might bust an extractor, a firing pin, springs get weak in time. Like all machines certain parts are expected to be replaced, and around 5000 rounds you might think of replacing all springs when you replace your barrel.
If properly lubricated your receiver will effectively last forever. Your bolt will last darn near forever also. There are couple of reasons you might replace a bolt, if you have so much gas leakage and primer piercing that you eat out the firing pin hole, or you eat off the bolt face. I doubt you or anyone you know will ever experience this, you would have to shoot crates of crappy ammo.
I know a guy on his fifth barrel, he is using original operating rod, gas cylinder, trigger group, stock, flash suppressor, buttplate, handguard, etc. He replaced the bolt because his hand loads etched the bolt face and he did not like it. Probably was safe, it just bothered him. The receiver developed a non load critical crack on the fifth barrel above the bolt stop and Springfield replaced it for free.
Considering he has shot about $6250 worth of ammo through that rifle, he has gotten his money worth.
