While Tesla is or was production constrained it does not make sense to add new models. Once EVs become commodities the competition shifts to this and that feature, i.e. models. This issue should be viewed in terms of where Tesla and the industry are terms of development and adoption.
But there is more, the question is not selling more cars but making decent margins and profits. The auto industry is a phase-transition mode from selling hardware (decreasing returns) to selling software (increasing returns). The recent change of plans at Tesla from the mass market car to the RoboTaxi is an indication of this phase-transition. The mass market car is the right choice to sell more hardware while the RoboTaxi is the choice to sell more software but it has additional risks, will the software be good enough, soon enough to get the necessary regulatory approvals. Besides hardware is more standardized world wide than driving conditions which complicates adoption (localization).
A recent thread mentioned the divergence inside Tesla between the more futuristic Elon and the more conservative executives.
I read this after posting! I see that you are in the same frame of mind, TaaS vs. ownership.
The Captain