I have a somewhat different perspective regarding the need for assistance. Most of my diving in SE Florida is on boats with rec divers using a backmount single cylinder, sometimes with a pony. Not infrequently, there are divers in backmount doubles or divers with a rebreather. Sidemount is very unusual with the operators I use.
I don't believe I've seen the divers with doubles or a rebreather receiving extra help from crew. However, I have dived many times with divers in a backmount single who, for a wide variety of reasons, have required, and received, extensive assistance from crew to be able to dive. This often consists of the diver sitting on the dive platform and having a crew member bring over and assist them in getting into their BC and cylinder. They do a forward roll into the water and execute their dive. At the end of the dive, they remove their BC and cylinder in the water and it is taken by the crew. Some of them also require assistance in reboarding via the ladder.
On my last trip down to Florida, I made the acquaintance of a man with a congenital bone disease and many corrective surgeries, leaving him with residual deformities and weakness of his back and lower extremities. He was a very experienced and skilled diver with an incredibly good attitude. He usually dived 3 times per week, on weekdays, when the boat was less busy. He did most all of his own prep but needed the assistance to get off and then get back on the boat. Over the 4 or 5 trips I did with this gentleman, I developed a lot of respect for my new friend.
So, the amount of extra assistance a diver might need is between the diver and the boat crew. I would not begrudge a diver the opportunity to dive if the boat crew is able and willing to supply the assistance required. Of course, safety issues are a separate topic and must be taken into consideration. Sometimes I stop and ask myself, what if that person was me? I would really appreciate the opportunity to dive, as long as I was able.