I honestly think that if you have a short enough runway that "who will be productive quickly" is a prime concern, it may be time to consider hiring nobody and figuring out other ways to save money and extend runway. And if you aren't that desperate, then you should stop asking this question and instead ask "who will be a good investment longer term?".
Alas, that's not how the market works, unless you can pay top of market. So for FAANG, that works, but for startup #293928293 that won't work. They need to ship more features asap (an orthogonal discussion about building the right features is a different matter), and for that they don't have time to bring someone up to speed, only for them to jump to a better paying role once they've upskilled.
I've worked at all different kinds of companies, and I don't think this is the way it works at well managed startups.
The model I've seen at startups is an approximately two-year cycle of 1. raise money against a couple year plan of milestones, 2. hire quickly on the back of that raise, 3. use that personnel growth to hit those milestones, 4. go back to 1.
Importantly, the large bulk of the hiring happens around those post-raise points, when there is a couple years of runway. And the idea of startups is to be ambitious and forward-looking, not myopically churning on short term features.
I would submit that it's even more important for startups to be focused on investing in the right team during those scale-up periods, because many of those people are going to be the leaders during the next round. You want people who are going to be strong stewards of your business as it grows, not just people who see themselves as "react devs" or whatever.
