"Political base" is kind of a confusing term these days. The Trump base is composed of at three disparate demographics, which likely won't get along with each other if asked to work together.

Probably be the same for the Democrats.

But I would say the upper-middle class to the slightly wealthy are D supporters and bring in at least 5% of voters to the D way. That cannot be ignored in a country that has many close elections. And these classes do donate to political causes.

Political pundits have little idea of the immense balancing act politicians must make. While Mr. Biden is probably in favor of the four points mentioned, his balancing act required him to scuttle them--before they got on the legislative docket. That 5% (or 9.9%) may not be that noisy, but they are a powerful demographic.