Bitcoin safe if ECDSA is broken?
First, if ECDSA were broken, a lot of other things would be broken, like ssh, https and a bunch of other things, including banking websites.

Second, if nobody reused addresses, then yes, bitcoin would be protected by SHA256 and RIPEMD160. There is currently no known way to get a preimage of a hash used by either of those functions so your bitcoin would be safe. Again, this assumes nobody reuses addresses.

As far as how much protection this gives, it's hard to say because it depends on the exploit used to break ECDSA.