Well, the question is: what’s your criteria for “they will last”…
If the criterion is “software support” then it’s nearly impossible to say.
FP1 was not supported long but this was because of the SoC used. So FP improved and used a different brand for the next models.
FP2 still gets SW updates after 6 years, but no one knows how long.
FP3 and FP4 get SW support but are still not very old.
If criterion is how long people use it then you should have a look at
and
Other criteria?