[formerly_proven]

I wouldn't be particularly worried of someone decrypting a file encrypted in the 80s using Triple DES anytime soon. I don't think I'll live to see AES being broken.

I wouldn't bet on the TLS session you're using to have that kind of half life.

[loup-vaillant]

There are two sides to this coin: one is the actual strength of the primitives involved. RSA is under increasingly effective attacks, and though elliptic curves are doing very well for now, we have the looming threat of Cryptographically Relevant Quantum Computers. Still, without CRQC there's a good chance that X25519 and Ed25519 won't be broken for decades to come.

The other side is the protocol itself. Protocols are delicate, and easy to mess up in catastrophic ways. On the other hand, they're also provable. We can devise security reductions that prove that the only way to break the protocol is to break one of its primitives. Such proofs are even mechanically verified with tools like ProVerif and Tamarin.

Maybe TLS is a tad too complex to have the same half life as AES. The Noise protocols however have much less room for simplification. That simplicity makes them rock solid.