Maybe they are just scared old grumps out there thinking that they might lose their money if Bitcoin suddenly dump. Maybe they also think that their decision has been justified especially when they see current bearish situation happened on Bitcoin. But hopefully they realize that they made a wrong assumption on Bitcoin and open this topic again then make this plan come into reality.
Don't be so quick to judge them when we are not them and I believe if one of us had billions of dollars we would also have different thoughts and decisions about bitcoin. Just because they are not rushing to invest in bitcoin, we should not judge them and assume they are making a mistake. If they were people who kept making wrong decisions, they would not be able to become rich, own billions of dollars and become shareholders of a corporation with a capitalization of up to trillions of dollars.
I believe they have their reasons for not rushing to invest in bitcoin and just because they haven't invested in bitcoin doesn't mean they won't invest in it in the future. The rich have their own way of playing, they can invest after us, buy at a higher price than us but they will get better returns than us.