2^80 is a lot of work, but it isn't enough to be considered secure by current standards.
Actually it is more than enough:
If all the parties of the bitcoin network with the current hash power of (almost) 2^62 H/s reach a consensus and decide to just find one single 160 bit collided pair of keys, they have to devote their total power for the next 1000+ years or so to do the job. (Note: we have to run 2 hash functions in each test).
Check your math. 2^62 hashes per second does 2^80 work in 2^18 seconds. That is three days.
you need a memory size of 2.4 * 10 ^ 25 bytes. And even applying algorithms that use a trade-off between memory and calculation time - it will still be a huge size.
No it won't. Collisions can be found an an effectively storageless manner with a small constant factor slowdown, I gave google terms upthread.
You're suffering from the same ignorance that caused the collision design flaw in "xthin" where they were claiming that collisions of a 64-bit hash were infeasible to compute due to storage requirements. (which I eventually eventually grew tired of correcting and started responding to all the messages with 64-bit sha2 collisions.)