I don't think it's that the pharma industry is being negligent. It's that it isn't an easy problem to solve. The process of building bone is complex because it's a constant cycle of breakdown and renewal. Look at all the drugs that have been approved so far:

Fosamax 1995
Forteo 2002
Reclast 2007
Prolia 2010
Tymlos 2017
Evenity 2019

Also, there is always research going on. For example, they are working on a pill form of a parathyroid drug (currently Tymlos and Forteo, both injectables.) And, they are developing models to determine what sequence of drugs works best for certain patients.
https://www.labiotech.eu/best-biotech/osteoporosis-research/