Good point Seashell...but you must be YOUNG! When you get to be my age, you learn to pack lighter (as in never pack a bag you can't carry yourself!)
But there are ways to get around that...like adding racks to the back of the golf cart! Many possible solutions to the luggage carry problem.
As far as taxi drivers who have bought vans, well, they can sell them on the mainland...the town board might well provide a free ferry to those taxi drivers who need to sell their vehicles. Here again, these are not insurmountable problems. It would have to be phased in, obviously.
There are tropical islands that do not allow cars. I have some friends who vacation every year on a little island, I think its called "Abaco" or something like that, or maybe its "Turtle" something, not sure, but they do not allow any motor vehicles. And people vacation, they stay for weeks and manage to get their luggage to their hotels with no motor vehicles. (Yes, they have golf carts and bicycles!)
I do not perceive any insurmountable problems that would be caused by a phase out of non essential (very limited construction and ambulance vehicles excepted) motor vehicles. Adjustment issues yes, insurmountable problems no.
San Pedro has become so congested with HUGE motor vehicles and the accompanying "crowded" feeling, noise, stink, huge ruts and potholes, and potential accident danger (some of those cars speed, laws or not) that it has lost much of its quaint beauty. The water is still wonderful and the restaurants and gift shops and bars are still great, but the town streets no longer have the lovely ambience they once did. That's my opinion, anyway, others may disagree. And that is a net negative from a tourist perspective, I believe. It is something that can, however, be remedied if the residents are creative enough to attempt it.
We all have opinions, but the people who live in San Pedro have to make these decisions. Luckily, I think its one of the few that they may be allowed to make without interference from greedy pols in Belmopan...maybe???? I don't know how local people feel about the increasing number of cars. Perhaps it does not bother them as much as it bothers visitors and part time residents?