Y'know the original poster got me thinking (oops, danger sign there) and so I was re-reading this entire thread.
What's wrong with scenarios and even entire campaigns using the Traveller system but never needing a starship, a starship is not central to the plot? Companies publish these modules all the time.
GDW - CT - Divine Intervention. In reality this covert op could be on the same planet the characters are hired on to begin with, the floating 'temple' (lack of better term) is in another country... Kind of like a EU company sending a merc crew into Iran (just an example).
T/S Games - MGT - Somnius Munde. Get railroaded by the cops, forced to raid a warehouse as agents of the police but without a legal warrent. Maybe you rode in an air/raft but they aren't mentioned, heck you don't even go NEAR a star port.
Now there are two examples, one Traveller canon the other recent third party license. If we,as the fan community were to demand that "ALL" Traveller scenarios involve starships in a significant way, wouldn't we be telling these two publishers, and every other publisher of similar scenarios, that they are 'wrong'
There are many types of scenarios that can be well run using the Traveller system, even in the 3I setting... but demanding that everyone feature starships prominently is like demanding every single D&D scenario must be in a dungeon and feature some fearsome dragon.
To me that doesn't make sense, and is very very limiting.