Before Gen 2 dropped we got an event to help us finish gen 1. Now we get raid update suggesting maybe they removing all or most of gen 1 poke from eggs to replace with gen 3?
Before Gen 2 there was an event in a time when the game had kind of got dull as everyone had finished (or almost finished) thier pokedex. . The same happens here
Before Gen 2 there was early release of some gen 2 pokes. Same again here.
5 months before Gen 2 we got the buddy system a new way of getting candy. Now 5 months ago almost we got the raids system, a New way of getting candy.
7 months after Pokemon go’s release we got gen 2. That’s a Pokemon about every 2.1 days. Following the same rule 281 days after gen 2 gen 3 would be released. That is 9 months 10 days roughly, putting the date at 25th November (coincidentally today’s date as of writing this).
Please remember that this is all speculation and pretty random. I personally expect Generation 3 to drop Early December with some new items and maybe a new level cap (50 maybe)