The party that just gave the largest tax cut ever to the 1%ers.
That's operates on the assumption that money is the only form of "currency" out there, and the only lever of power and influence.
When you boil it down to practical terms (and how the two parties pander to various rich people):
One party says (to a small group of uber wealthy people) -- if you back us, we'll make sure you get to keep an extra $400k of your income rather than paying it to taxes, and we'll get some of those inconvenient regulations out of the way for the businesses that you own.
vs.
The other party who says (to a different group of uber wealthy people) -- if you back us, you won't get the tax break, but we'll make sure the institutions of academia, entertainment, and 75% of the mainstream media promote your preferred viewpoints on all of the non-economic social issues to influence the public over to your side, and we'll occasionally try to squash opposing viewpoints on your behalf.
Basically, they're appealing to two distinct different types of "thirsts for power".
One is mostly greed-based based, with a dash of "I have a lot of money, so I want to be able to get rid of laws I don't like that prevent me from making even more"
The other is more power craving that involves wanting to be able to manipulate public viewpoints in order to have everyone else think the way they do.
If I may use a Batman villain analogy to describe which types of rich people the 2 parties appeal to...
The republicans appeal to "The Penguin" type of rich person,
The Penguin doesn't seek to prove philosophical points; he simply wants to be rich, respected, and feared. His crimes are almost purely elaborate (ethically compromised) business ventures designed to have more money -- regardless of who it hurts.
The democrats appeal to the "Riddler" type of rich person.
The Riddler wants people to acknowledge his "genius" and see the world through his lens. His strategies are elaborate demonstrations designed to reshape how people think about intelligence, authority, and who deserves to hold power.
Or to put it more succinctly, the Koch/Mellon ilk and Soros ilk are two very different types of billionaires motivated by two very different types of power. The former just want a lot of money (and the removal of impediments that could stop them from making even more), the latter enjoy the ability of being able to manipulate people into seeing things "their way", but making it feel like it was their own choice.