That is the fallacious paper millionaire argument. They have more than enough liquidity, can take loans against their “non-liquid” wealth, and are anyway working with multi-year plans to sell assets and have enough liquidity. I believe this is also explained in https://mkorostoff.github.io/1-pixel-wealth/ and there they also explain that the US market cap is bigger than their stocks and so. So they could sell a lot in one go, of course losing “efficiency”, but the market would be able to cope without any issue.
I think we are on the same side here judging from the rest of your comment, but I find it important to refute this typical argument, because it does not help that there is some sort of billionaire apologism by saying that they “don’t actually have this money in their bank account to spend”.
It’s getting downvoted to oblivion because it ignores many things, namely the fact that a lot of drug research worldwide is state-funded. There are many cases in which pharmaceutical companies use public funds for R&D, and then go on to sell the drug at steep prices, raking in immense profits.
Meanwhile the public has to either cough up the bucks, or wait until the patent expires to have affordable options.