Football,like all things in life evolves through time.
When I was a schoolboy the following teams were in the Football League(usually 3rd or 4th Division.)
1- Workington Town
2- Barrow
3- Southport
4-Bradford Park Avenue
5- Stockport County(in the FL until much more recently tbf)
So basically Bury and to a lesser extent Bolton Wanderers have failed to adapt to 21st century football conditions and have ultimately paid the consequence for not evolving like other teams have done successfully.
They have become football dinosaurs,and we all know what happened to the dinosaurs.