I totally agree with you. I have worked for 25+ years for an airline so have been fortunate enough to travel alot. San Pedro was one of my favorite places even though it is more expensive. Three factors I have noticed that could hurt tourism...
1. Airfares.... airfares to Belize are much more expensive than places in Mexico, Costa Rica, and other places in the Caribbean. I'm not saying you cant find occasional good deals but overall pricing is slightly higher. Plus you add on additional fares from Belize City to San Pedro. I always chose the expensive route of Tropic Air versus the water taxi, mostly to save time.
2.Hotel pricing.... Hotel prices are comparable but most places I have visited in Mexico and the Caribbean were all inclusive hotels. I haven't seen these in San Pedro.
3. Departure taxes.... I hate these... feels like you are being held hostage and have to pay to leave the country. These vary by country, some higher and some lower.
I love San Pedro and return mostly because of the friendliness of the locals. I hate seeing the rise in crime and wish they would get this under control. Every time I suggest Belize as a travel destination to someone they usually say they heard its not safe. This perception needs to get changed or tourism will decrease.
I hope all works out for the best for the people of San Pedro. I truly love this place.