I think that really depends on a couple of things: 1) Why is he falling? It would most LIKELY be due to a poor injury prognosis, meaning he might not be available until 2021. I mean his tape is already out there, he's not participating in any bowl games or the Combine, so what you have on him is what you have now. Could Ballard be that patient? Well, that all depends on 2) Sign a veteran FA for 2020 that Tua could learn and grow under while he is recovering, then let him take the reigns in 2021.
Now, would Ballard want to do that? THAT is the $200M question. But I would be OK with it.
Ballard has hit on far more picks than he's missed on. Hopefully most reasonable people will pick up on that.
We have more cap money than just about everyone (I think we actually have the most cap space in the NFL right now). Not sure who the contender is that'll outbid us by $3 mil/year.