there's a very good reason why Sims 4 has not implemented wheelchairs yet.
I keep seeing people on the internet say something along the lines of "If the Sims can implement dogs and horses, they can implement wheelchairs!" And... well, no. The issue is a lot more complicated than that.
For the record- I'm coming at this as an amateur Sims 2 modder who's tried to figure out how to do wheelchairs a couple of times and have not been able to figure out how to do it to my satisfaction. If I sound angry, it's not because I'm mad at you; it's because I'm mad at myself for not being able to do this.
So. Before we talk about wheelchairs, we first need to talk about what a Sims dog is, under the hood. In every version of the game, functionally? It's a Sim in a fursuit with a distorted skeleton. You can see that in some of the horrifying Sims 3 glitches where the dogs stand up on two legs and start looking like very distorted people.
Dogs are Sims that are locked into a particular set of animations, and locked out of a bunch of other animations. Dogs have to run on all fours; dogs cannot offer other sims a rose or hug them.
Remember this; it will be important later.
To make a wheelchair-using sim in Sims 4, you need three things: the wheelchair itself, code that tells the wheelchair and the sim in it how to act, and animations for the Sim to use while in the chair.
The chair itself is moderately easy-- you would just need a couple of really good 3D models, and a wheelchair isn't exactly rocket surgery. The code would be more difficult-- you could probably repurpose the bike code, but there'd likely be some major hiccups, especially with indoor pathfinding around small objects.
But the thing that absolutely kills wheelchairs dead, the thing that makes them a nightmare to implement every time, the single thing that means we're never getting wheelchairs in Sims 4, is the animations.
See, if all you wanted was a chair a Sim could sit in and move around in, that would be one thing. But most of the people who want wheelchairs don't want them to be a funny-looking bike. They want to be able to make a sim who uses a wheelchair in their day to day life.
This means you would need to remake every animation in the game to be doable sitting down.
Think about that for a second. How many new animations did you get for dogs or vampires or werewolves or mermaids? How many is that compared to how many animations are in the game, total, now?
How many animations require your Sim to stand up before doing them? How many look weird if you're doing them with Sims of wildly varying heights?
Added to this: you know how BIG and EXAGGERATED all the sims' movements are? That's deliberate- they're meant to be easy to read at a distance. You would have to rework them all so that the animations are easy to read, even if you're looking at the Sim from behind and like 90% of the sims' body is obscured by the chair.
....Animation is the most expensive part of game dev. Like, hands-down, bar none, the most work and effort. It's the place where a lot of indie games go to die. And reworking every goddamn animation in the game to be legible and look good, even if one of the sims is in a wheelchair? That'd be an incredibly expensive undertaking.
And this is before talking about the social concerns that come up every time you're portraying a marginalized group! It'd probably be easiest for the devs to portray ambulatory wheelchair users- but is that the only group of people who get to be portrayed in game? Or are you going to take the time- and the assistance- to code in transfers and wheelchair-pushing?
It'd be easier for the devs to make "wheelchair user" a lifestate that can't hybridize, so they don't have to redo all the vampire/werewolf/witch animations-- but this means you've locked an entire group of people out of all of the fun of occult simmies. Is that a tradeoff worth making if it means you get wheelchair users in the game, or is it unfairly discriminatory?
And this is before factoring in the fact that people will- rightly or wrongly- judge disability content way more harshly than they'd judge, say, dogs. You'd basically have to give it away for free, or you'd be accused of being a cash-grab designed to exploit the disability community, even if it's the best implementation of a wheelchair ever seen in a video game. Any inaccuracy, no matter how small, becomes "proof the devs hate wheelchair users".
....And might I remind you, this would be one of the largest and most expensive animation projects that the TS4 team have ever done. You cannot expect people to do that for free.
So yeah, it's an incredibly big, complex project with absolutely no ROI. You cannot expect the TS4 devs to be able to accomplish this. You would basically need to work wheelchair users into the game from the ground up.
What they can add, and should, are canes and crutches. But that's another story.
