I think I read somewhere that ECDSA was broken and if it were the only encryption our keys would be toast, so basically bitcoin is standing on two remaining legs since there are three layers of encryption. This is all far beyond my level. Oh, it was saying that's why spending from the same address twice endangers your keys. The only take away that I understood well enough to stick was that you should always spend the whole txo and change should go to new address.

But that seems worrying. Seems like there are two ways Bitcoin has already broken - doubling blocksize means miners have to centralize, and ECDSA being knocked out means future attackers have less work to do. At least, that's how I hear it. I'm painfully aware of my lack of understanding.