Quality control specifically for the Model 3 or quality control for the Model S? Clearly the Model 3 quality isn't good enough right now, but it seems quite likely that given time they should be able to bring it up to Model S levels. I don't know if that's good enough, but I think it might be. Will Tesla have time to reach that quality level? I think they probably will, but they may have to raise more money to pull it off. And they may have to raise that money at a less than favorable valuation. However, the idea that they won't be able to raise money at all seems unfounded to me, just like the implied notion that they can't fix the quality problems.
There's a big difference between "Tesla is struggling" (yes they are, and it's not even the first time) and "Tesla is going to fail".