Its useful to do the math around what your equity would be worth, if you are the 50th hire you are probably getting less than .1%, so even a crazy moonshot billion dollar acquisition would leave you with a few 100k at most. Grinding yourself down for a slim chance at making that amount isn't worth it.

I have had managers say things like: "this could be the last job we ever work" as if none of us are capable of doing math.

That said we are all a bit prideful so exhausting yourself to get that fleeting feeling of having achieved something clever and good is definitely on the table.