If anyone wants to know why Viking does not encourage scooters or wheelchairs, you should realize it is the same reason they make us pay deposits a year ahead in most cases. It's because they can.
When Tor started Viking Cruises, he decided to do a cruise line he would want to take, add all the things he would want and not worry about the things he wouldn't. Then, provide such a great product that loyal customers would put up with a few things being missing. If you want to go on Seabourn, Regent, Oceania or which ever other cruise line because you can take a scooter or get an accessible stateroom lower than a suite or pay a deposit only 3-6 months in advance, Viking is willing to have you do that because they have lots of other people who will take your place. Their ships and riverboats always seem to sail full or they do a last minute sale. Either way, not a lot of empty staterooms around, just a bunch of very loyal cruisers.