This reminds when EA released Sim City in 2014 and they said the game had to be online only, because of the ammount of data needed to be processed and the cpus couldn't handle.
LOL.
Yeah, what really happens here is a lack of development from Frontier Developments.
We don't need to go as far as planetary landings or walking around, just seeing how the game was developed in this 4 years is enough.
They did unit simulations of several cities by per citizen so yes, they needed online component. Have you played offline version of SimCity 5? It is a nongame. Nothing happens, because sim part was indeed on servers.
Now, why they wanted to create such game and then only reveal that 1 month before release is another question. Just saying your analogy is a bit flawed.