Nothing really changes.
Climate change? Too late.
Wealth inequality? Neither party really wants to change that. (Not with any affordable or sensible program.)
Getting ahead of the impact of automation on labor? Nah, fuck that. Nobody's interested in that. Adam Smith says that'll self correct over the long haul.
Both parties are owned by interests that usually want the same thing: Policies that benefit them and allow them to make more money. They only differences are some of the companies give more to Ds and less to Rs and some give more to Rs than Ds. Some give equal amounts to both. A few only give to one side.
The Ds are a good purchase because they control things by making promises to the population, and sometimes actually follow through. This keeps the people left behind in the changing economy feeling like somebody's got their back. This keeps things stable, which is something the people buying Ds like. You get to make your money, feel like you're a good person, and not worry about instability.
The Rs are good purchase because they flood money to the people who own them. If you've been holding a lot of Ds, but your profits have been a bit weak lately, it's a good time to buy more Rs. They'll give you a giant tax break. They don't promise the little people many things, so there's less stability than there is with buying Ds, but that's the tradeoff you make for those lower taxes.
And both parties do something all of their owners like: Factionalize the population. By selecting policies that are anathema to each other, and marketing themselves to the persuadable, they drive the population into camps that fight each other. This is a most important benefit, because this keeps people from aligning true majority power against the people who own the Ds and the Rs.
Sometimes, even people who fancy themselves smart and well informed will get in arguments with each other over these competing policy menus and marketing strategies which are designed to keep them divided.
