I tend to disagree that they couldn't be flooding the market
Basically, I have no access to the data how much oil they have in their reserves left, and I guess no one here does, if anyone at all (apart from the KSA royal family, of course). These were just rumors, after all (though they have been circulating for quite some time now). Other than that, there are quite a few things in the world which are totally counterintuitive at first glance (close to incomprehensible) while at some deeper level they are quite logical and rational. For example, Saudi Arabia might be flooding the market with cheap oil like mad even if their oil reserves were near depletion because it would still be more economically justified. We could have even lower oil prices when Iran started to produce crude oil at their full capacity in a few years after upgrading their oil extracting infrastructure
If you're close to depletion though, what short term benefit are you realizing by flooding the market now and realizing less revenue in the midterm? Saudi Arabia is not a diversified economy, and if they're close to depletion they are setting themselves up for great economical and political instability in the near future. It's possible as you say, but I wouldn't bet on it
I wouldn't bet on that either
But they might know something which we don't. For example, it would make sense to sell oil at any price if they desperately needed money, even if their oil reserves were close to depletion. After all, oil is still almost free for them (the cost of extraction is something like a few dollars per barrel). Yes, they had something like 600B dollars in wealth funds, but these funds are mostly in US treasuries (read they are controlled by the US government), so they can't simply convert them to dollars and take the proceeds. By the way, does anyone know how much they have in their funds by now?