The same thought occurred to me, but I've done a playthrough of NMS with the teleporters removed and found it to be a love-hate thing. While the increased sense of adventure, exploration, etc. is nice without a fast travel mechanic, there are times you just don't really want to spend (literally) hours of real time merely to get from one of your own bases to another.

An idea I had was to set a limit of how many total portals can be constructed and to remove the return of materials on deconstruct, as well as increase the construction cost itself. With a limit of something like 1-per-boss slain and no return of materials, you'd still be able to use portals for main base locations, but couldn't use them as a crutch for 'everything'.