Makes me wonder why Arnold kept pumpin' weights his whole life. it certainly didn't make him any weaker.
Granted that I no longer gig but when I did I had to lug an organ. I helped the drummer with his gear and he helped me carry the organ. The guitar and bass player always complained about having a sore back. Go figure.
So, if you think a keyboard is too heavy for you, don't buy it. Get a lighter one. I just don't understand why it's necessary to make it an issue for no amount of complaining is going to change anything.
As for myself, I only care what I get in voices and styles. Weight is the least of my worries.