It has taken one decision from theymos to create a migration of several higher ranking member to at least one other crypto forum. They simply followed where the money went and to be honest most members here are here for the money too. Overall, I would assume he took that in to account before making the decision and would probably do it all over again even if he knew the outcome because he did not want mixers that do not use coinjoin advertised in the forum.
The barometer to gauge the real impact of migration to other forums will not necessarily come down to what happens here because those migrating will keep posting here to earn whatever they can whilst they post over there to earn whatever they can, therefore though traffic should not decrease here but it will definitely increase there. As that (and other forums grow) this forum will not necessarily be the first place for crypto newbies to register.
If we have this conversation after on year, it will be interesting to see exactly how much the competitors to this forum have grown versus the rate at which this forum has grown.
Bitcointalk isn't a company. It's not operated for the sake of turning a profit and doesn't require revenue to continue existing; at least not for decades, or maybe even longer.
Bitcointalk is not a company and a forum without traffic is not a forum, it is a relic or a ruin, like the Roman ruins that people visit, not a forum. If hypothetically tomorrow there will be no more traffic on the forum, it will surely continue to survive because it will not need money, but it will not be a forum, it will be a ruin.