I always thought this but now that it's laid bare...oof.
I always presumed the final plan would actually have this path be the exit, and that is the reason the building remained, as it will serve as Tron's Giftshop as well as Space Mountain's exit shop. That is an odd way to enter the area if it is the only one.
Even so, they don't really care. They will just virtually queue it and control the flow for a while until it is not that big of deal anymore. Disney is not in the caring business of such things anymore.