It surely depends hugely on the job and the disability/s?
I work in IT. I've worked with a guy in a wheelchair - he could do everything except one or two bits of physical work with handling computer hardware. He did once go for an interview where there was no step-free access to the building, which they failed to mention beforehand
I've had/have a number of deaf colleagues who are usually fine with hearing aids. One has a cochlear implant. Sometimes you just have to remember to speak to their better side, or where they can see your face.
I have a friend who is blind, and is a department head in a secondary school. I think it's very pertinent that he became blind as an adult, and already had an established career record. I think it would have been a very different story were he starting from scratch in his career. He's currently in the private sector and they happily coughed up for some very swish tech to read documents (even handwritten ones) for him. It has made things more accessible for him - and it cost money that the state sector just couldn't spend. When he was last applying for jobs, there were schools he declined, because they weren't as accommodating. He's also been quite upset at points when his remaining sight has declined further and he could no longer make out children's faces and so on.
I don't know about colleagues with mental health issues. I probably have worked with some, but I haven't been aware of a formal diagnosis, and as I'm not HR nor their line manager, why should I? I am I a particularly techy area of IT, and I suspect quite a few colleagues over the years may be autistic, but I'm not aware of any with a formal diagnosis - but again,why shoukd I be?
I think physical but mostly stable conditions are probably easier to accommodate. It's the ones which flare up, or cause burnout, meaning attendance is less predictable which is more challenging for employers; it's easier to manage a team when absences are planned, not like having a team member where you're never sure if they'll be in that day. Conditions affecting mental ability will also restrict the sorts of jobs possible for someone - many jobs do require staff to have a certain level of intelligence.
Larger organisations are probably more able to be more flexible as a general rule, because if you've got hundreds of staff, you've got more options in terms of hours, job shares, physical and mental abilities. A staff of five usually means you just can't change much and still cover your operating hours, but it does still depend on the exact job/business and particular role. A guy with one arm might not manage well in a physical warehouse role, but would be fine in accounting (assuming he's had the relevant training.)
But I think slso, there's still a lot of prejudice out there. There will be employers who don't want yo put in a wheelchair ramp or won't see how more flexible working patterns could benefit the business, not just the employee.Or they're making assumptions about reliability and attendance or just about (in)ability to do the job, or don't want to bother with perceived extra paperwork etc.Not that they'll necessarily say that overtly, EA2010 and all - "the other candidate just haf more relevant experience," etc.