Of course the level of proficiency is of utmost importance. But the vast majority of non-arranger musicians have no idea the technology even exists. I think some of us are assuming most musicians look down on arrangers. I disagree. Most musicians are totally ignorant about high-end arrangers and don't have an opinion. My original point was that they don't know what they are hearing. It either sounds like good music or it doesn't. Your level of expertise determines what they hear. If it sounds rinky-dink, then you need to learn to play better and/or examine the capabilities of your gear.
In past years I would often have drummers or bass players mention that I was costing them a job. I've got news for them; if they were any good they wouldn't be worried about my taking their job. Most all my jobs have been in venues where they wouldn't have live music at all if they had to pay a really good 4 or 5 piece band. But I don't hear that anymore. They are now used to hearing background tracks, Ka####e, etc.
Years ago, before arrangers were invented, when I was playing just organ, using foot pedals, later adding a drum machine, it was easy to find work. By today's standard that would sound hokey and old-fashioned.
There are thousands of piano or guitar players using pre-recorded tracks to do one-man acts. The arranger lets us have so much more flexibility. I can changes songs on the fly without missing a beat, extend a song as long as I want, turn it into a medley of songs, make a song into a totally different genre, etc. Just like a five-piece band could, except I don't have to teach everyone else in the band.
I think I'm just about the last person in this entire area to do a successful arranger act at a professional level.
It's interesting that none of the guitar or piano singles can take my jobs, and the ones that hear me, without fail, want me to explain the technology. I am glad to oblige, but I make it look very hard.
I can pick up their guitar or sit at their keyboard and pretty much do what they do. They CAN'T do what I do.
As DNJ says, why am I defending arrangers? I hope nobody else around here ever discovers their true capabilities.
This forum and a few others are the only places where I can go to discuss arrangers with informed users.
I understand that in many European and other countries, arrangers have much more wide-spread use and acceptance, but in the U.S. this little niche in the entertainment world has kept me from having to get a REAL JOB for many, many years and I will continue to embrace the technology for a few more years. I hope.