Ship interiors are a great example of what I mean, actually! Let's dive in, shall we?
Because they are so ravenously demanded by a portion of the players, adding ship interiors to the game is going to be a massively difficult undertaking for Frontier, because there is literally no way they can get it right enough for people to actually like it.
Let's say they add ship interiors "just enough", for that sweet sweet immersion factor that everyone demands. You can walk in your cockpit. You get some hallways, maybe a lift to take you down to the airlock to disembark. You get some pre-fabbed dynamic areas where if you outfit a cargo hold, you can see a cargo hold. None of it is interactive beyond a walk-by, but it's there and you can move through it in all its glory now. Let's say just to make this fun, the blue teleport circle is still there too, so you can choose to disembark with a teleport or walk through the ship manually. The ship interior is implemented, but totally optional! Everyone wins, right?
Wrong, and I guarantee you knew why before you got through that paragraph: People who want ship interiors want more than just the immersion of looking at it, even if they claim they "just want to walkabout in the cockpit". No they don't. The immediate next demands are gonna be "Braben said we'd be able to repair damage inside the ships in the kickstarter", "what about EVAs", "I want to interact with these computer panels and have it mean something", "where's my Captain's Quarters?", "I want an NPC crew I can see and give orders to". If all we got out of an eventual ship interior implementation is "walk around in your ship", people who claim to want that will celebrate for about ten minutes and then demand to play with it in a more engaging way. And for folks who want it to be optional, and who unironically continue to use the teleport disembark? That's going to be decried as trivializing interiors, and that FDev is bad at game design because they allow it to be bypassed.
Now let's flip the scenario. Ship interiors are functional. You plot your course through the stars on a dedicated Universal Cartographics star mapping module. You can repair your modules manually from the inside of the ship, and you can EVA to repair the hull breaches on the outside. You get a fully customizable Commander's Quarters, ranging from a simple bunk in the Viper III to a full blown Stateroom in your Anaconda. You can go down into modules like a Cargo Rack or a Refinery to see what's in there, repair it by hand, maybe even take part in enhancing its function or constructing something like limpets. People can board your ship/sneak aboard just like Braben said in the kickstarter. Amazing, right? Dream come true!
Except it's not, because if you're gonna make that gameplay mean something, it's going to re-balance the entire game in ways that can't be opted out of. Wear and tear on modules might need to be increased to give you a reason to interact with them, which means tedious maintenance gameplay loops. AFMUs now become optional, which means the "ideal build" might not include them, so now why are those in the game any more at all? If there's a mini-game inside a refinery module that slightly increases the yield of an ore payload if you work it manually, now the only correct way to mine is to engage with that tedium for every single chunk of ore you break off. Don't think people will play that way? Look at how people treat Engineering now. If the game allows for sneaking onto or forcibly boarding a ship and stealing it, is that going to be a rebuy or have you lost that ship permanently? Either way, having to fight people inside your ship (NPC or player alike, because there will have to be NPC boarding attempts if the system exists) is now non-optional. Decorations for your Commander's Quarters? If you can earn them in-game, they're a grind. If you can buy them with Arx, it's a greedy corporate cash-grab.
All of this considered? Unironically, as it stands now, the game actually does work pretty great without interiors.