Destiny 1 will still be playable, dont worry.. The only things being discontinued is anything that is considered a "live event", such as IB, trials, and festival type events. Weekly resets and weekly activities will still be there.

The only change is the loss of any future events, Iron Banner and Trials. Everything else stays as it is now.

As far as anyone knows while there will be no more updates you will still be able to play Destiny 1 for sometime. Weeks, Months, Years hell it could be around till Destiny 3.

I think this succulently puts it what happens What will happen to D1 in short few months: Decay! Cut the tongue you speak with to say Don't believe, don't believe it The wrong way, on a path to somewhere Don't feed the selfish mouth of man Born into a life that depletes me Your empty words have burned you And condemned you another day Again you mean nothing