Rasputin:
...people who are still doing OK (or even very well for some, I imagine) tend not to post here because they don't want to sound like they are showing off when it is clear lots of people are earning less, and also because they don't have a problem they want to discuss.
As a result you are not seeing a representative sample in these threads and it is not easy to know in % terms whether most publishers are doing better or worse than a few years ago.
I'm probably not 'a representative sample' and I certainly don't want to sound like I'm showing off, however just so you know that the shared doom and gloom in this thread - it is obviously regrettably real and chronic for a significant group - is but a trailing edge of the AdSense publisher graph.
It is critical to remember that things can vary greatly by niche and site and location and competition and what have you. For my sites, all sort of within one overarching vertical niche (none in the 'highest paying'):
* for the past several years mobile RPM has been at a ~6% rate growth premium over desktop.
---it currently (on average) is almost a third premium over desktop.
* currently (on average) smartphone CTR is ~120% higher than desktop (yes that is right: double plus a fifth), ~60% higher on tablet than desktop.
Note: sometimes volume makes a positive difference.
* however, the mobile breakout is not close to even; in order of ad publisher value:
---iOS app (growing YoY at ~3-times Android rate) ads,
---Android app ads,
---smart phone browser ads,
---and bringing up the rear (at ~1/3 discount from smart phone ads) tablet browser ads.
Note: I do not display third party ads in my apps.
I'm one of those fortunate people who have done and continue to do well with AdSense even as I've phased it out (from 90% of pages to 10%) for direct ad space sales. Why? No secret sauce, just a good business model, a solid business plan, and a whole lot of work over the years.
Reference Note: in my niches third party advertising networks are currently paying at a minimum 80% discount from direct ad space rates; put the other way: direct ad space on mobile is selling at a minimum 5-times third party ad network rates. Some more than double that.
Note: this is one reason that I don't have AdSense in my apps; it does make good defaults/filler for browser pages though.
Thought: it would be interesting to chart the correlation between niche AdSense rates and direct ad sale rates, I have noticed that the more advertisers are willing to pay directly the more I've been making via AdSense RPM. If there is a causal link then doing whatever it takes in your niche/location to become attractive (quality of site and visitors) to direct ad space buyers could be a win (significant new revenue) win (significant AdSense revenue increase) situation well worth the effort.