Coinbase is big but they have nowhere near the money, legal reach, engineer head count, or infrastructure of a Microsoft, Facebook, google or Amazon.
if the rumors of Coinbase making loads of money are true then they make a great and vulnerable target. I mean Coinbase is the US leader in crypto but they don't really have any moat around them to prevent one of the big 5 from coming in and competing with them by slashing trading cost to almost zero.
Where would Coinbase be if trading commissions were gone.
That's got to be a "Netscape loosing all its Navigator revenue due to a free Internet explorer" type scary for Coinbase.
Even if Coinbase is making money like crazy, you'd think they still have to seriously consider selling.