History is rife with hundred-billion dollar industries destroyed in very short periods of time, across multitudes of field types.
For example, i've watched fields created by single legal opinions, grow to many billions, and then get destroyed overnight by a different legal opinion. All in the course of 10-15 years.
The amount of money in it is just not a sufficient condition for it to stick around. It certainly helps, mind you, but there will always be somewhere else to put the trillion dollars.