You seem to have a good grasp on this, so I'll ask you: why are things set up such that recruiters are "Joe Random Recruiter" to me, rather than "Joe, who I have met, worked with across multiple job switches, and who relies on my trust"?
I've known the founder of the company for about 5 years now and he is well respected within the communities he operates in (Ruby on Rails, iOS, DevOps, etc)
There are people that stay in contact throughout multiple switches, but it's pretty rare. Staying in touch after getting you multiple jobs presumes they are likely in agency and that they still work on the same type of roles. Agency turnover is high so they might not even be in recruiting after the first year. Then also take myself, I worked on varying roles from finance, healthcare, mech eng, swe, ml, pm, and more all in the last 2 years. Chances of me working the exact type of role I got you into a year later is unlikely.
Its a tough market to serve because the most people don't change jobs more than a couple times in their career.