This is really a two part question, because there's shortage and then there's the fact that 1000 rounds of 9mm I paid $150 for a year ago is now over $600. Let's remember Obama, just him being in office and the media talking about gun control every couple weeks kept ammo prices high and availability low for YEARS even though they were never even close to passing real bans etc. Doesn't matter if Biden can pass anything, he's very anti-gun, it's on his agenda, he's going to try and push it and the media will push it and support it. That alone will keep prices high and panic buying rampant for his entire term even without a single anti-gun law passed.
We know all the things that happened during Obama, you had shops holding supply down to keep prices high, you had shop employees buying all the ammo arriving and reselling it on Gunbroker, you had shop employees calling their buddies when ammo came in and it never even saw the shelves, and you had guys buying up every box of ammo they could from stores that charged reasonable prices only to resell on gunbroker or gun shows. You had LEO/MIL making much larger orders than normal because of the ammo shortages as well. Then when the average shooter found ammo that the above didn't get at reasonable prices, they bought every round they could. Now on top of all that, you have all the covid fear, riots, etc. and record numbers of new gun owners for months now that all want ammo too.
My bet, 2025 before we see availability and the prices we had a year ago and only if Biden loses in 2024. Honestly I expect in the near term we are going to see high capacity mags and any "evil" guns go up in price and be hard to find as well, I'm honestly surprised it has not already happened. If you believe Trump will pull a rabbit out of his hat, maybe mid 2021.