Since  when?...There has been plenty of original and innovative ideas from  filmmakers back in the 30's,to the 70's that were not remakes or  reboots. Actually some very good films.
		
		
	 
Since the  beginning. The first several waves of films were nothing more than  adaptations of books or plays. An original story was a novelty.
		
 
		
	 
I think you are pulling things out of your arse.....
Are you trying to tell me that MOST of Hollywoods movies back in th 40's to 60's are reboots????
		
 
		
	 
Actually, I do know what I am talking about, and you seem to be under a very misguided belief.
For  starters, when I refer to the beginning of Hollywood, I am talking  about the 10s-30s.  This is when Hollywood was actually new.  Also, you  are slightly putting words into my mouth.  I didn't say everything was a  reboot back in those days.  To be honest, I hate how the term reboot is  being used and abused as a buzz word.  The term adaptation or remake  would be better suited. 
Regardless, if you look at those early  films, especially the ones that are still looked on as classics today,  you will find that many of them are not original-to-film ideas.  Many  are adaptations of plays and novels (and even comic books!). 
Film  was a new invention at the time and its profitability in the long run  was still uncertain.  So, what did movie producers do?  They made films  of stories people already knew!  That way, people would go and see them.   It worked for the Greeks, so why not Hollywood?  Even two of the most  well-know of early film making, Le Voyage dans la lune and The Great  Train Robbery, were not original ideas, but adapted or remade from early  works.
Over time, more original ideas started to be made into  films, but even then, many of the movies made were based off of  something else. 
Then, by the time we reach your time period of  the 40s-60s, we saw more unique stories, but many were still based on  other works.  We also began the first major waves of remakes!  For  example, how many Broadway musicals were adapted to film during this  period?  Or how many Dracula, Robin Hood, or Sherlock Holmes movies have  we had over the years?  The answer is tons!
Back to my original  point, remakes and adaptations have been going on in films since the  beginning.  It will continue to go on until the end.  The idea that  people are complaining the Hollywood does it more now is strange, since  it is on par of what Hollywood has pretty much always done.  I will  admit, however, that the marketing of things being a reboot/remake seems  to be more in-your-face than ever before. 
	
		
	
	
		
		
			^  Perhaps not most, that would be a fairly time consuming stat to  assemble. But it's extremely common for a film to be based on a book, a  play, a musical or, history permitting, a previous film, and it is no  more the case now than it ever has been.
		
		
	 
Yep.