I kind of saw that coming. Sold my best site 2 weeks before Google medic update a few years back, the site lost 90%+ of its traffic. And I sold my last Amazon site 3 months ago. Here are a few facts.
1. Amazon doesn't need affiliates any more. They needed them, but not any more. Google is packed with Amazon niche affiliate sites. If there are 500 affiliates fighting for the 1st page in SERP, Amazon doesn't matter who gets the commission, someone will. If they are left with 30 biggest players in Amazon Associates program and pay them normal 6-8% commission, they can cut much of their bureaucracy staff. There will be no help desk dealing with thousands of affiliates asking stupid questions about OneLink integration, there will be no need to talk to thousands of affiliates asking why they didn't receive their checks, etc.
2. Bezos is the richest guy in the world. He doesn't give a shit about you, your family, or anyone else. He never will. If he could, he would robotize the entire business process of Amazon and sit on the iron throne like that degeneric incestuous Lannister bro. He'll never have concious. If he will, he'll just donate 0.001% of his net worth to a charity and he'll sleep like a baby.
3. Most people whether reading reviews on niche sites or not, will buy something on Amazon any way, so small time affiliates are pretty much useless to Amazon. It's a hard fact to grasp, but if you were a small time US Amazon affiliate in the past 5 years, you weren't making Amazon a favor, Amazon was making you a favor. International Amazon sites are another story since Amazon doesn't have a monopoly there.
4. There's no alternative affiliate program for most products sold on Amazon because prices on Amazon are usually the lowest for the same thing and most consumers aren't stupid. Years ago I switched affiliate program from Amazon to Walmart, promoting exact same products. Conversion wasn't 5% or 20% lower, it was about 80% lower. I found another store that had affiliate program, and they didn't even bother to accept me into it although my site was pretty much dominating all the important keywords in the niche and I'm sure I'd made them shitload of business back then. I found a third affiliate program that offered 20% commission on the same products and I was thrilled. But... The price for the same product was $174-194 on Amazon and Walmart, and $400 on the "20% commission" affiliate program. It was a damn joke. On one of my sites I was selling 1k$+ items and I always thought that 24-hour Amazon cookie hurts me the most. Because there's less impulsive purchases on expensive products than cheaper ones. I switched affiliate program to a smaller distributor who had exact same prices as Amazon, same day shipping and had 60- days tracking cookie. Instead of getting 10x $1000 sales, I got zero sales in 1 month.
5. This isn't just Amazon, it's internet marketing in general. There's always a chance you'll lose much of your revenue on any given day. The more you sleep on your success and the more you stop evolving, the more chances you have that you'll get raped and you'll have a harder time climbing back up. Had a friend doing mass Youtube commenting spam. Got to $15k per month, invested shitload of money in order to catapult himself to $150k per month in the next few months. In a few days he got raped with a Youtube antispam update and the 6-month run went to shit. Got a friend who ran porn sites before PornHub existed. One day Pornhub got traction and all the "premium" porn sites with 60€/m access fees got down the toilet. It's internet marketing where shit happens all the time. SEO, affiliate marketing, CPA... It only takes one man to push the button and you are screwed. Diversify your income sources and you'll have more chances of surviving.
6. There's still shitload of other affiliate programs to make money in. But most of your "best electric toothbrush" and similar sites are pretty much dead now, you can take that to the bank.
7. There's nothing you can do about it. Amazon is a $1.1 trillion company. It was at the right place at the right time and became one of the largest businesses in the world with a business model that no one will be able to ever replicate because times have changed.