Because they know that they won't directly benefit, that it will pose a threat to the old power structures they are in control of and know, because conservatives (and old people) by their nature are scared of progress and new things, because giving in to some level of equality would mean that they were wrong on any number of other things and that conservative ideology might not actually bring about the best possible society.

They see themselves as naturally privileged, and anything that may pose a threat to their power dominance will always be fought, just like in feudal times. It was never about money for them, the money was only a means to an end, to make sure social division and hierarchies were upheld and protected. If you start messing with the money, however, that would be the first birth pangs of a new revolution, and they know whose heads are going to roll.

Giving a fair share to everyone, even hypothetically, would be like admitting that the Emperor doesn't wear shoes, and then socks, and then pants, and then all the other things and then all of a sudden we find them standing there ~~all nekkid with their dick in their hands~~ like a bunch of old fat white dudes jerking each other off in the middle of the town square.

E: Edited for poetry