Please direct me to that as I did not see it in the interview. Verbatim what you said.

About half way down they explain year one weapons wont get random rolls only year two onwards. By that reasoning new vendor weapons available in places like Vanguard and Crucuible and possibly planetary vendors will have new random gear for people who don't own Forsaken.

See once again it’s speculation. I’m not banging on your belief but it is not a definitive answer.

I agree, whilst it's not Bungie coming out and definitively saying it, logically it seems to be the case. I believe it's safe to reason that since Random Rolls being a seasonal update and certain vendors receiving new seasonal gear that this is more than likely the case. They'll have a very limited selection of gear to grind for but the box would technically be ticked. Although I wouldn't put anything past Bungie at this point. If they do screw over people who do not purchase Forsaken it will undo a lot of the good will they are slowly getting back.