I don't know if I'd say "quickly"...it eventually caught on, and may have ultimately been in emulation of what Star Wars films had always done, but it was still pretty common for films to have decent-sized opening credits into the 2000s. (Though yes, much longer credits at the end.)I think I read that George Lucas got in trouble with the unions for holding the credits to the end on Star Wars in 1977, but the practice quickly caught on and now it's uncommon for a movie to show its credits at the beginning.