What does that 'include more children' look like though? If certain kids need specialist provision, and can't be in mainstream classes or cope in social settings etc, you just get separate, segregated "inclusion units" in the grounds of a mainstream school. How is that different from a separate special school?
One difference is that it's cheaper than a separate special school. Only one teacher (to run the unit) because the class teachers are in charge of the pupils' learning, even if they aren't accessing it. TAs aren't specialists, so are paid ordinary TA rates. SALT once a week, if you're lucky, OT once term. Unit isn't funded like special school.
Another difference is that it's not purpose-built, so the space used may not be fit for purpose.
I know an autistic, noise-intolerant child who fears people coming up behind him - his safe space, study space and breakout 'room' is a corner in a wide internal corridor outside his classroom. He spends virtually his entire day in this area, with his unqualified TA 1-1s (job-share), who do their best to support him and teach him.
In the meantime, children who almost cope in mainstream are left to struggle and fall behind because they aren't getting the support they need, whereas children who could do well in a special school aren't getting anywhere in mainstream because it's totally unsuitable for them.