I wouldn't say it's just FE - many of my recruiter friends have this problem with ANY senior developer. It's low supply and low turnover.
Additionally, it could be your job posting not being enticing enough to get hits. I'm a senior FE dev and I saw some pretty bad job postings (hostile programming assessments, unpaid take home assignments, a circus of interviewing rounds). If you don't have your salary listed, that could be the issue too.
I can't speak for everyone here, but I'll take 2nd or 3rd best in compensation if the interviewing process isn't a 3-ring circus. ie, I will actively drop out to protect my time from bad interview pipelines.
My last two gigs were less than 2 hours of total conversation before a contract got signed, as an anecdote. Hell, I had one that was a 23 minute phonecall (it was awesome!). Some people just know how to hire someone after they look at a good LinkedIn or GitHub profile.
Just my 2 cents. As a selfish plug, you could talk to freelancers who have the expertise you need so stuff gets done in the meantime. It's not ideal, but at least you'd have the help...