Gen 3 was data mine in Pokemon go. Probably releasing next year same time as johto did this year

Red and blue

Gold and sliver got VC

same year as the Pokemon was introduced in Pokemon go

Gen 3 only gen you can't play on 3ds or switch. So gen 3 VC next year makes sense

So sinnoh would be next in 2019 Pokemon go but instead of vc I think there gonna remake D/P

Remakes dates
2004
2009
2014
2019

Every 5 years

So makes sense