Ask HN: Why are software developers not more like lawyers?

I've been thinking a lot about this lately, and there is probably a really obvious answer..

But considering lawyers and developers are both knowledge workers, why do you think the majority of lawyers work at private practises (law firms), yet the majority of software developers work at corporates, enterprise, FAANGS, startups etc?

I spent 8 years running a small software agency, and when now I look back I realise that was more like a law firm. Small, specialised, experts.

Why don't developers more commonly 'band together' to form a software development firms?