Four months to receive an offer? Come on. You get the vast majority of the signal for a candidate in the interview process itself. All of the backoffice deliberations don't require months of meetings. It's just more okay that it gets dragged out because the market is lousy.
Call it what it is: indecision and inefficiency.
It's definitely not going to get you the best candidate, but it might get you the cheapest one.
(In retrospect I should have followed up with them, as the new place was throwing red flags).
they either needed the exact, perfect candidate, or else they wasted a lot of time
I get that a business may always want to be open to hiring an exceptional person if one becomes available, but that's very often based on an internal recommendation/reference not a response to a job posting. Execptional people generally don't apply to posted jobs, they work their network.