Depends on the type of loan. I don't think any of the premier league clubs generally use the loan system for young players particularly well apart from say Man United.
Spain and Germany don't really use it too often as they produce through their B teams playing competitive football. Additionally, there are more cash strapped sides in those leagues, so they will always give youth a chance and let them play.
Here's a decent article on what happened to Josh McEachran at Chelsea -
The loan system in football is something which has become more and more of an option for clubs recently, but does it really work for all concerned? Is it simply like living together before you get married? Try before you buy? Or is it evidence of an employer not really rating a player but giving […]
taleoftwohalves.uk
There doesn't seem any close contact with these players from academy to senior team that you get in Spain, Germany, or Holland. Hence why players disappear