Yes, I understand that hiring is always a big decision - which means you need to build trust. This would explain the low % of end conversions, but the question of low interest at top of the funnel (e.g. conversions from HN of PH) still remains.
Going back to your business: I'm replying to you now but I already forgot what the business is called (I had to go back to the post to check whether you had even mentioned it). I will forget again in 30 minutes. I can recall indeed's name instantly because they've been on the radio daily for the past 3 months (and not to rain on your parade, but their pitch is the same as yours - "faster hiring"). And if not indeed, I can recall ziprecruiters name because they've also bombarded me with marketing and I can recall this small recruiting firm in Toronto because the way they reached out to me was legitimately personalized instead of the generic mailmerge crap you often see. So if I were to think "hey now I'm in need of some milk", which recruiting companies do you think will pop up in my head? That's managing top of the funnel, IMHO.
The three approaches I see most often are: mass marketing (e.g. what indeed/ziprecruiter/etc do), bringing in clients from your networking connections (presumably one would have a decent amount given 5+ years experience) or cold calling (basically everyone and their mothers in linkedin). "Build and they will come" isn't that viable of a strategy </two-cents>