GPON has a bunch of modes, some of which are symmetric. Notably a 1.2 Gbit/s down/up setup for gigabit service. Many modes are choosen to be asymmetric, yes, but the technology is not intrinsically one or the other. Notably, just like non-multiple-access fiber connections increasing upstream speed doesn't negatively impact downstream speed (as it does for copper-based connections).
2.4/2.4 is also a standardized GPON speed... Just not very common.
But either way it's irrelevant to the point that the technology can very well support symmetric speeds and offering symmetric doesn't "need a lot of "active" equipment and that drives the costs up." as the commenter I originally replied to claimed. Also evidenced by XGPON having the exact same amount of active equipment.
For what is worth, I haven't had much contact with technology in the last couple of years and things might have changed. My comment was based on my last experience where GPON by design was asymmetric and if you wanted symmetric speeds you would need an MC on both ends of the fiber, hence de "active equipment" need. And then from the MC to a router or whatever you had there.
On the other hand, more than 300Mbps upload is quite ok even with heavy video conferencing and what not.
