Well on your last point, the future of tech is always difficult to predict. What I love about it is that you wake up in the morning, and who the fuck knows what is going to have happened?
That being said, I truly feel like header bidding and all the stuff happening in Ad Tech is really great for publishers right now. I got my career started in this space as a direct sales guy for a niche site, and we crushed it. I have spent the last 13 years of my life closing direct deals, and funding wonderful media sites in the process. That feeling of being the guy that enables the content crew to do what they do is extremely rewarding to me.
The problem is, more and more clients are giving the excuse of "Oh well sorry bud, I put half my budget with google this year.". In the past as a direct guy, you'd have looked at this like a disaster... but with the power of header bidding - where you can truly expose your Tier 1 inventory in a fair price auction - those spends are coming back to you. Sure, Google or whoever takes a cut... but to be honest once the tech matures more... its probably a more efficient system than me calling the marketing guy and cutting a deal with a silly piece of paper sent through a fax machine.
I do think you're right that there is some parts of the system which are just giving a temporary boost, and there's going to be a ton of changes which happen as this moves forwards...
But the bottom line is that with (properly) implemented Header Bidding, you actually can expose your best inventory for a fair price. On the publisher's side, it changes the game a bit where you want to focus on aggregating a valuable audience, but that is a strategical re-alignment vs. a complete destruction of the business.
I also want to say that what I think is amazing about this is that from the people I talk to on the buy side of programmatic - they want quality inventory. They really want ads to be displayed around good content, and they're willing to pay premium CPMs for it. They don't want to be in the arbitrage or total click bait game. They want the good stuff.
My dream for the world is that this header bidding revolution is the start of great publishers actually making the money they need to fund quality content. There's a huge problem with it admittedly where its also what has funded fake news/content farms/everything bad with social media... but I don't believe that is the future.
TL;DR - Header bidding rules.