You said
>Anyone who would make software with your framework would be in violation of several laws.
Which just isn't true as there are ways you can comply with EQA without every underpinning library being accessibility-compliant.
Say I am a British person who decides to make a some common piece of software, like a spreadsheet, and offer it for download on the internet. Am I required by law to make it accessible? And if, for instance, the provision of accessibility features would require thousands of hours of redevelopment, does that fall under "reasonable adjustments"?
I understand that the moment my software becomes required for someone's job, for instance, there might be a problem, but a few posts up it was implied that making software without accessibility features was in itself illegal in some way, and that just sounds doesn't sound right to me.
Section 20: https://www.legislation.gov.uk/ukpga/2010/15/section/20
That does not call out in its table any reference to software. I can't see anything in it which would effect a binding to software products. Section 22 refers to regulations being able to define what are "auxiliary aids", so in theory an SI may have done so.
Scanning the whole Act, the closest thing I can spot is Schedule 25: https://www.legislation.gov.uk/ukpga/2010/15/schedule/25, however even that defines it as “any service normally provided for remuneration, [...]". Note that is for an online Service, not a Good (which software would generally be). I've also not found what references it.
So that may cover a web site, but only if it was a paid for thing (e.g. online newspaper sites accessed via subscription). I wonder if and how it applies to the likes of Amazon, where the site itself is not paid for, but goods available through it are.
So unless someone can find specific references, I see no reason to believe there is such a statutory requirement in existence for software, certainly not for free software.