The easement for the parking spaces for the HT residents ends on the expiration date x-x-2021. The residents can continue to park in the garage, and pay for it. Without the easement, they simply don't have a 'right' to a space reserved exclusively for them,
After reading through Chiofaro's most recent submission to the city, I have come to believe that the city has a say in the future use of the garage. Chiofaro goes on at truly great length about how many parking spaces will be available by time of day for Aquarium visitors during M-F, and on weekends. And it strikes me that he feels obligated to provide x number of spaces for the Aquarium.
Going back to 1971, the city built a 1400 space garage, reserving 300-400 spaces for HT residents. What about the other 1,000 spaces? There was little parking demand in that area 50 years ago. It may be that the garage was built primarily to provide parking for Aquarium visitors, and the city has now told Chiofaro that his development must provide a comparable number of spaces in the future for Aquarium visitors, or else no construction permit. And it also may be that there is a legally enforceable stipulation associated with the original sale of the garage to a private company, and which applies to subsequent purchasers of the garage, that 'guarantees' x number of spaces for Aquarium visitors.