I think arrangers loops and all that stuff can help a creative person a lot, not as much as a creative tool, but as the means of getting inspiration for a new creation..
And then there is the fact that musicians vallue other things then the publicum..
I have two friends that make their money as an OMB. One is the best musician i have ever met, playing evevrything live on a stage piano and even performing his own songs, but he has an average voice at best... The other one can barely play a chord on his arranger, but has a top knotch voice and is a born entertainer... Now guess who makes the most money on his gigs?
And then there is all those deejays creating their own dance music in their daws, and making millions of dollars with just a simple beat and half a mellody. While a highly educated Jazz pianist with outright skills has a 2nd job as wayter because he cant make enough money from playing music.
Personally i think its not the musicians making the big money anymore, its the singers and the deejays, and the rest is nothing but support...