Frequently, at least in the UK, both the SETS and COSTUMES from professional productions are sold off to hire companies and then leased to amatuers. The sets and costumes can then dictate that the show follows the original quite closely e.g. in terms of choreography.
A good example is LA CAGE (in which I was a Cagelle!!), the three opening chorus costumes i.e. COATS, PYJAMAS, SAILOR pretty much meant that the routine mirrored the original. We even had the ROBIN WAGNER show cloth and deco back drops. Together with the arrangements there is not a lot you can do to avoid copying the original opening number. The owners of the costumes where original London Cagelles and so reproduced all the hair and make-up changes too.
Other shows which came out to amatuers complete were 42ND STREET (Broadway/London revival) and IRENE (London Production which was stunning) and I am sure there are many more. CRAZY FOR YOU was leased to amatuers and you could buy the rights and directions for all the original choreagrapy (Susan Stroman)
There are also many licensed companies who reproduce the original sets for hire with no credit being given to the original designers so maybe your beef is with them??
Don't knock what the amatuers provide as despite there being many more excellent tours there are still SOME productions that don't make it into the Regions and all this for a price that most people can afford.
"Your eyes..... they shine like the pants on my blue serge suit"