The idea is that you don't want to be secure now, but also in the future. The ECC Bitcoin uses is vulnerable to Shor's algorithm, and thus quantum computation. Quantum computing at that scale is a fair ways off, most likely, but on a timescale of a couple decades or more, a successful attack seems quite reasonable.

Bitcoin can soft-fork, allowing address generation with a different algorithm. It's not any sort of existential threat to Bitcoin. But it does require that you move your coins to a new address if you reuse an address, else you are vulnerable.