grow our economy from the bottom up and the middle out.

[GoodTaste]

Joe Biden just tweeted:
Our Build Back Better Agenda will strengthen our economy by lowering taxes on the working and middle class, and reducing the cost of child care, housing, and higher education.
We will grow our economy from the bottom up and the middle out.

Source: https://twitter.com/JoeBiden

I understand "the middle out" as "(grow our economy from the bottom up) so that most of the people will enter the middle", am I on the right track?

The problems in this understanding are: (1) Progress can be sustainable and so people from the middle class can still go upforward - That is, they will not be "out"; so I guess that, politically speaking, the middle class is the genuine force that makes America great and so making the middle is the top priority for any administration; (2) the top class is always a small group of people, it can't be "the top out" - that is logically and practically impossible.

I am not sure. What does "the middle out" mean?

 

[emsr2d2]

I read it to mean that the aim is to bring the people in the working classes "up" so that they join the middle classes and, as a result, the middle class will get bigger (it will, in a way, "spread out").

Note that we say "upper class", not "top class" when talking about classes in society.