(In reality the distinction between slave and employee is blurred over thousands of years and it's hard to use our words to talk about their setups. It's likely that both slave and non-slave labor (taking slave to be unpaid coerced labor) was used; just as our society uses both, either openly or discretely.)
The local church down the road from me can bring out a TON of people to work for free for various activities, and they're upset if they miss out.
It doesn't seem unimaginable that non slave locals in Egypt would be similarly motivated and even enthusiastic about working / being a part of it all.
"Prisoners with jobs" are becoming something more people know exist, as opposed to a niche dirty secret, which I think is probably a positive sign of reform rather than an indication of deeper normalization.
I imagine being common citizen back then is terrible, if only relative to my experience, but on the other hand they may have been enthusiastic to contention to an important religious activity. Really hard to know their circumstances / point of view.
They are paid but aren't they technically slaves at that point if they cannot quit?
https://www.theguardian.com/world/2013/sep/25/revealed-qatar...
What if pyramid workers were like that? Came and started to work, realized the insanity of it all and wanted to quit but if they did they would be killed, starved or blacklisted?