IanCP, it's difficult to know precisely and is your loss of traffic definitely a Google Search problem? Like many others, I used to do well with Adsense just by concentrating on writing content. Traffic has always been up and down, but I've seen a gradual decline since the beginning of 2014. From October 2015 to May 2016, in particular, was a disaster regarding traffic. When I started having success with affiliates at the end of 2014 I removed Adsense for a couple of years. When the affiliate money started to dry up I tried Adsense again, but it was still bad. Very few clicks and very low EPC, with quite a few 0.00 clicks.
Like you, a big problem was loss of traffic. As you say, less traffic equals less clicks, and also ad quality goes down with less traffic. It was getting to the stage a few months ago when frankly it wasn't worth continuing, but I thought I'd at least make a final effort before giving up altogether.
I had never given much thought to SEO previously. We're told content is king, right? So that's what I concentrated on. However, a lot of content that was ranked much higher than my content on Google was lower quality (IMO). I have 15 years experience in my niche and have language skills and other knowledge that many competitor website authors don't have. Sites written by newbies with none of the experience or skills I have were outranking me by a long way. I started reading up and watching videos on SEO - Neil Patel and Brian Dean have put a lot of good stuff on-line. I was quite shocked at what I found. My SEO was virtually non-existent (because I had never given any consideration to SEO) and it was no wonder that Google wasn't ranking my pages. It also became obvious that my competitors were concentrating 90% on SEO and 10% on content. I probably did OK up until five years ago because there wasn't much competition, but the situation is very different these days.
Recently, I have been trying to rectify this problem. No rocket science - just basic white hat SEO techniques that are freely available on-line. I've been doing keyword research, rewriting some content, optimising HTML title tags, HTML H1 tags, etc etc. Also writing some new content.
Nothing happens overnight, but I've been seeing a gradual increase in traffic and yesterday had the most traffic I've had since the end of 2014. I'm continuing with my changes and expect traffic to increase quite a lot more in the coming months. Before it struck me that the loss of traffic might actually be my problem I had blamed Google search, but now it is obvious that I was at fault. When an algorithm, not a person, is evaluating your site your content has to take that into consideration and you need to give the algorithm a few clues.
What about Adsense? Well, despite the increased traffic recently Adsense still isn't good. Yesterday was a great day for traffic, but another dismal day for Adsense. However, I am hoping this is because there is a lag and once Adsense realises that my traffic is increasing it will start to perform better. We shall see. Even if Adsense doesn't start performing I am hoping that the increased traffic will boost affiliate earnings. When my affiliate stuff is going well it makes even 'good' Adsense days look insignificant. It's good not to have all your eggs in the Adsense basket and I also have plans to create some of my own e-content to sell later.
