Another niche. If you do anything highly variable / custom - think music concerts - you can target very specifically towards demos for that artist and get amazing ROI. Run the campaigns for one artist, take a similar artist, no digital promo - FAR fewer folks showing up.
Now in terms of third party stuff - total trash. There is a reason google wants to track you on the web. My guess is as the privacy push gets stronger, that third party network stuff, which is already weak, will fall through the floor, because the tracking is not only for ad targeting but some is designed to help (a bit) with fraud prevention - which is a massive issue on third party networks (and I include Facebook's non direct advertising etc here).
1) For sure the state of online ads right now is overhyped. But to claim it's therefore all a bubble and you can't derive value from targeted instagram ads, or adwords doesn't withstand basic scrutiny.
2) The subprime mortgage crisis collapsed the way it did because money was owed that couldn't be paid back. This is not the case here, the money is simply spent with no ROI. One could argue this is a positive as it means there is money in the economy that could/will be put to better use.
If google and facebook shrink gradually in the next 10 years this is a net positive imo. But to claim it will be a mass exodus, and collapse the market overnight seems a bit stretched.
