I've been a Linode customer for almost 15 years. As far as I remember, this is their first price increase ever. No surprise it happened post-acquisition :(
Linode's development has slowed to a crawl since this acquisition unless you start considering "Network updates to connect existing core sites to the Akamai backbone" and the likes as development.
Also, most of the time, reverting the increases would take renegotiating things with support. Recently, it changed into requiring destroying my machines and creating new ones from scratch, what besides an improvement, is still as hard as migrating to another provider.
Anyway, I was not entirely dissatisfied with them, but this one is a sleazy behavior.
This is strange, I've been a customer for a long time and never noticed that.