You probably dodged a stressful position. Companies or teams that can’t allocate time to onboard talent are likely poorly run and can’t afford to invest in people. “Contributing immediately” is a fair indicator of that problem.
There are so many hard problems in this industry. Onboarding is not one of them.
Typically what I have seen is that management is so busy striving for short-term deadlines etc. that they "can't spare" engineer-hours to help the new engineer properly. Heck, I've been one of the senior engineers that has not had sufficient time to spare for the new people - not by my choice. In other situations we've had new engineers inserted into our teams with zero notice -- so we've not even had the time to prepare some "day 1 wins" for the new person.
It seems incredibly obvious to me that great onboarding is a true force multiplier.
Last place I work paid a lot of fake lip service to the importance of onboarding. But the reality is that we were judged strictly by the numbers in terms of commits, Jira tickets closed, LOC, etc.
Word - I never considered this possibility. But now that you mention it, the hiring manager I spoke to had this smug swagger about him and a condescending sneer about my current company and open source in general. Not good vibes at all. As a member of his team, I might have placed myself in a position that is bad for my mental health. Thank you for sharing this perspective, really helped.