Not OP, but in general to be hirable in academia you need to demonstrate a constant flow of papers and grant proposals.

Being 'out of the game' for a couple of years means you have not published or applied to grants within that time. At best, you might be looking at restarting at the bottom of the ladder until you've reasonably caught up in numbers to climb back up again.

And it's not even just a case of "computer says no" because of automated metrics. In the UK at least, government initiatives like the REF mean that the university will actively avoid hiring you because by definition you would be costing the university money. (and conversely, you have an advantage for being hired if you demonstrate the right REFfable metrics, even if you weren't the most suitable candidate at the interview, because this automatically brings a university money that is directly linked to your recent REF outputs).

I don't know what the situation is like in the US, but I'm fairly sure similar exercises exist with effectively the same effect.

Academia tends to have fairly linear career paths. You do a doctorate, then maybe do a post-doc, then become a lecturer / assistant professor, etc. If you don't follow the path you end up without the track record (publications, funding, etc.) you need for promotion and will be passed over for other candidates who look more likely to succeed. There are many more applicants than positions in most fields.

If you're not on this career path, there is basically no alternative in most institutions. You can be an adjunct, or lab assistant, or other low-level employee forever but this will lead nowhere. This is particularly a problem in the US, where the tenure track system gives you seven years of grind to achieve tenure, and if you fail your academic career is basically over.

(Things are changing. Some institutions have, for example, teaching track positions.)

Academia is a guild. There are far more people who want the job that can get it, and has very strong employment protections for members. They don't welcome outsiders anyhere except the bottom of ladder.

Well, for one, people usually leave for systematic issues with academia that won't just magically be fixed over time.

Second, it's very difficult to get back in anyway, you will have a publication gap and with the extreme increase in publish and perish it's hard to imagine it being a good choice. Here in Germany, getting any permanent academic position is a pipe dream even for the extremely motivated. This ties back into the first point.

Cults sometimes don't allow returnees.