Yes, it would. 512 bit keys can already be cracked, which is why it's mind-boggling stupid that some PGP programs use that as a default key size. 1024 bit keys will probably be cracked in the next 5 years, so those aren't safe anymore either. That's why we recommend at least a 2048 bit key, but 4096 bit is better because it buys you even more time. So why don't we just use one million bit keys? Because it's computationally expensive to use them and that increases non-linearly with key size. Nobody wants to wait a few hours (or days or weeks) to encrypt a message. So there's a trade off: the level of security that we accept as convenient but still safe is usually something that can be broken in 20 years (instead of a million years), and we increase our security (in this case, key size) over time.