Yes the patriarchy needs to be challenged. And yes, everyday sexism is a problem that often fails to be noticed.
And yet….
I can’t get on board with Mrs and Mr. It sounds clumsy and awkward. I think it’s fine if you use the full names separately but not together.
Mrs and Mr Jones - no
Mrs Jones and Mr Jones- absolutely fine
I don’t think it’s just because we’re used to hearing Mr and Mrs, although undoubtedly that’s part of it.
I think it’s possibly more to do with how we use plurals in this country and how we structure those sentences. So we’d say Janet and John’s house. The “s” comes after the second name.
So although Mrs and Mrs isn’t the same type of sentence grammatically, I think it’s more familiar and pleasing to hear the “s” on the second word.
Undoubtedly misogyny and sexism are at the root of how this salutation originated, but I don’t think that’s at the core of why it’s used today.
And with more women retaining their surnames it’s possible to change those joint greetings to put the woman’s name first without sounding awkward for the sake of it.
Also, not all male and female pairings put the woman second. For example, the Bank of Mum and Dad.
I do think we should be pushing back on the small things - but not where it makes us look petty or ridiculous. And I think altering Mr and Mrs to Mrs and Mr is phonetically awful, and not a good hill to die on. Switch up other letter headings by all means though. That’s much easier to argue and entirely valid.