I'd say that's a crude reductionist view. See https://www.jstor.org/stable/2118406 to name one paper but there's tons of research on the link between capital markets and economic growth
What part of that crude or reductionist?
Technological progress being the sole driver of growth is the dominant view in macroeconomics. Even the paper you link attests to that.
It's reductionist because "technological progress" is too broad a stroke. "Productivity" is not directly observable or measured, right?
Access to inexpensive capital is a key driver of technological progress.
Robust capital markets allow for more efficient allocation of savings into business ventures, driving productivity forward
Loans are just move the money around and create “business cycles” of booms and busts. Which in my opinion exacerbate wealth inequality as opposed to reduce it.