Wait, but this is exactly what modern macroeconomics does by making a huge leap from microeconomic fundamentals and aggregating this into the Solow, Romer growth models and many derived upon models. It got so crazy that Paul Romer critices this approach himself in a well regarded paper last year: https://paulromer.net/wp-content/uploads/2016/09/WP-Trouble....

The austrian economists in turn don't pretend to know that macroeconomics work this or that way, they can make assumptions of effects that can happen due to policies, but don't attempt to quantify them.

I think the austrian school is largely ignored for two reasons:

- from it derives a very libertarian view of the world, which many people reject because of political views. after the WW2 libertarian views were not popular, so Hayek and Mises where largely forgotten. - because its philosophical approach is exhaustively researched and you cannot add more fundamentals, leaving economists with the problem of not having much to work on.