Donny, using all the features on an arranger keyboard requires a significant degree of talent - no shortcuts there, no crutches. You cannot play an arranger keyboard without some semblance of music education, whether it is formal or self-education. A person must be able to learn and utilize chords, know chord structure, etc..., all the same things a piano player, guitar player, fiddle player, harmonica player and other instrument players need to know.
And, when someone played a keyboard before arrangers came to be, they were essentially playing a piano, or organ - nothing more, nothing less, especially when they played with a band. When I was with a band, I played guitar, sometimes rhythm, sometimes lead, and I was the singer. The bass guy and the drummer, contrary to your belief, were playing repetitive loops, same as a style file, but they did it manually. We all had crutches, lyrics books, fake books, and when our drummer passed away, a Roland drum machine.
An arranger keyboard is not a crutch by any means. It is a fantastic musical instrument that is incredibly versatile. If you want to use it as a crutch, and some folks do by playing SMF files with embedded lyrics, or .kar files, then plink a few keys as if you were performing every sound in the song, then yes, it would be a crutch. Same goes for performers that do the same using MP3 files.
You have often stated that you rarely use more than a dozen styles for a 3 to 4-hour performance. Now that's repetitive, IMO. No different than some of the "Have Guitar Will Travel" guys I've run across in my travels. Every song sounds the same after the second song they perform. Today's arranger keyboards have hundreds of onboard styles, most of which are very, very good and can be used to perform any number of songs. Additionally, there are lots of song specific, third party styles available, which make that song fairly close to sounding like the original backing from the original band - and that's what our audiences came to hear.
Over the years, I have encountered several incredibly creative individuals on the Internet that produced some of the most wonderful music productions anyone could possibly imagine. They did this using low and mid range arranger keyboards, often with modified third party styles, and the skills of a creative genius - not crutches, as you call them.
Me, I made a damned good living with my arranger keyboard, I used it as it was primarily designed to do, and learned every aspect of the keyboard, inside and out. It took me years to learn how to do this, and during that time, I was able to impart much of that information to others along the way who were struggling with their keyboards.
Now, I can play a piano, though not very well, a 12-string guitar, electric guitar, a mandolin and harmonica, and while I tried playing a fiddle, I was never very good at it so I gave up on that instrument. Of all the instruments I learned to play, my favorite is an arranger keyboard. It is a fantastic instrument - NOT A CRUTCH!
All the best,
Gary