No demand for missing services

In sandbox mode, I have an emergency clinic and an x-ray machine. That's all I need. I have the x-ray machine because, at some point, doctors exhaust available options and need to x-ray someone, so I built it. But it seems like you never encounter patients after that whom have conditions or requirements you cannot fulfil. That is, you only receive patients you're equipped to deal with. I don't feel compelled to build more than just an emergency clinic if the game never sends me patients requiring such facilities (prior to having them).

I understand that if you build more departments you will receive patients that require them, but I really dislike this model. I think the game should push you towards building more facilities by creating the need for them, thus motivating the player to expand. It does not feel rewarding to build more than you need just to enjoy a greater diversity of patients because that's not realistic. Doctors consider diagnoses you cannot currently accommodate, but because I know how the game works, I can automatically eliminate them.

Having to chase new technology and facilities to cure new conditions is a positive motivator to continue playing sandbox.

I thought the whole idea of sandbox mode was to play with no one forcing you into anything. The playing is its own reward, for me.

I havn't tried what exactly the effects are of the "enable all departments" checkbox in the sandbox menu. But wouldn't it work that you could enable to receive department patients independently of what equipment you currently own?

However the way patients currently work, you get 30 ER patients per day and 10 specialized patients for each department you have. So if you were to simply enable all patients you would get a large amount of patients you couldn't treat, as ER patients can have any condition, including anything that's specific to other departments you have enabled. Which means you would only be able to treat like 20% of patients at the start of the game. I don't think this would be particularly fun or make for good gameplay progression.

As it works right now, as soon as you build a department clinic you are heavily incentivized to build hospitalization for that department. You might not get patients that require hospitalization yet, but doctors will assign patients with no obvious diagnosis to observation for more tests and once they are hospitalized in observation you need a hospital to treat them.

I disagree with the OP, especially in sandbox mode. If I want to make a specialist hospital I should be allowed to do so without being constantly told I really wanted a general hospital!

I feel like this would be a perfect case for a mod. There's a modding subforum you could ask there.