I've actually seen several arranges used on stage with bands, including Harry Belefonte's band when I saw it live in Baltimore many years ago. The player was surrounded by four arrangers and sat upon a drum throne. He was incredible and did an unbelievable solo. Now, I don't know about the bands in central New Jersey, but most of the bands I've seen during the past decade usually consist of a couple guitars, a bass player, a drummer and some vocalists. They rarely have horns or any other instruments. When I was asked to play with the Hubcaps many years ago, I used my keyboard as a piano, sax, trumpet and strings - the other band members loved it. In that band, they have a fantastic keyboard player who utilizes many of the right hand voices - not just the piano voice. And, he has two keyboards stacked on a two tiered stand.
Maybe in NJ they don't have a need for keyboard players in their bands, but they sure do in all the other places I've visited and seen bands performing. As to whether or not it's a pro instrument, who gives a shit! It will always be a pro instrument in the hands of a professional - it's that simple. And, if the younger crowds don't embrace it - well, that's just fine with me.
When you think about it, every instrument is essentially a home instrument. A piano, acoustic guitar, uke, banjo, etc... are all used more by home players than performers. Keep in mind that pro players of any instrument only make up a tiny fraction of those who purchase those instruments. I would venture a guess that of all the pianos sold worldwide, less than 1/1000th of one percent are played professionally by entertaining musicians.