The Democrats love using the tax code for social engineering.
They could easily pick and choose which types of assets (with minute differences between them) qualify and which do not.
This is the reason the tax codes gets bigger and more complicated....
Republicans are also very complicit in social engineering via the tax code. The Federal Earned Income Tax Credit morphed into a negative income tax during the Nixon, Ford, and Reagan years. Of course with assistance from Jimmy Carter and the Democrats.