To put numbers on "enormous piles of cash", Apple books $20 billion in profits a quarter [1] and $245 billion cash on hand [2].
My guess is that if they are looking for risky plays, there just aren't a lot of options for the amount of cash they have.
[1] https://www.reuters.com/article/us-softbank-group-vision-fun... [2] https://www.cnbc.com/2019/01/29/apple-now-has-tk-cash-on-han...