I have no problems with affiliate links not being disclosed. Why does it matter? If they're providing a useful link to someone, I don't care if Amazon gives them a few pennies as a reward. If their link is not useful, no one is harmed.
Sure you might not bother buying the keyboard after clicking through but the affiliate link is tied to you for x days, so they'll get a bit of cash of anything you buy in that time.
Why is it a problem if it doesn't cost you? It costs you the time to read it. Disclosing acknowledges this potential and explains what's going on in advance so you know you're not just reading trash someone wrote to make a quick buck.
What if you found a 2k to 5k word article on something you really wanted to know about and maybe buy.
Also what if that person spent 5,000 hours over 5 years building up their site and only 5% of the posts on their site has an affiliate link for something.
Would you discard that post as trash / scammy because they happened to drop an affiliate link into it because they personally used that product for years before writing about it?
IMO you can't really gauge any of that just by looking for an affiliate notice or not.
I don't make the assessment by looking for affiliate links. I make the assessment on undisclosed affiliate links, which I believe the article was at the time. It's one of many things that could indicate an article written around affiliate links and nothing is perfect.
You've since added disclosure so it's a moot point now :)