I guess people are appreciating the support and update cycles they are getting from mikrotik and would like something like that for PON networks, which start to be everywhere nowadays.
well people would anything from anyone, perhaps.
but with limited manpower, time, money - managers&engineers always forced to pick priorities among options/milestones.
as for "PON everywhere" its already sounds like joke. i just saw company, shifting from EPON to "active optic" and one ISP that ditched their GPON endpoints in favor of g.fast copper DSL links(cheaper, faster)so that would be quite unlikely if at all.
outside countries, focused on bulk surveliance on their population - there isn't much interests in PON solutions, because technical, economical inferiority of(especially in long-term), management and lifetime nightmare and vendor lock-downs.
i guess MT consdier adopting GPON/GEPON support, but only if they had opportunity and in unpredictible distance/timeline and not very likely, just like xDSL stop being mainstream(eg interesting)part of market.