For a quite a variety of reasons, actually, but I guess they mostly boil down to the main two mentioned, just above.
(Mine - in case you were thinking of asking - was that I was able to earn considerably more that way, by trading in
far bigger size, while doing almost exactly the same things, and losing almost none of the benefits of self-employment. Others I know in similar positions have other, only slightly different reasons.)
Indeed ... and actually one with which many employed traders disagree.
(But in the context of this thread, it's all kind of academic: many prop-shops are very scammy outfits, and they're the
only ones who are going to look at someone in his 4th year and not profitable as a trader.
No disparagement intended, but it is what it is.)