My ads were working reasonabilly well considering the low investment I was making, with a fair amount of prospects filling my contact form on a low but steady rate. I was satisfied with the return I was getting.
However, the pandemic caused a significant drop on my product's demand. I thought I was going to get little to no contacts from the moment the lockdown was announced on, but:
1) I kept getting clicks at basically the same rate -- therefore my budget kept being depleted as it used to be;
2) Bounce rates increased A LOT;
3) The few actual people who got in touch were not actually looking for the product I announced, but similar ones (which I didn't announce nor sell);
So, according to my experience, I can't say adwords totally doesn't work.. but I'd say their algorithms are optimized to spend your money regardless of the results you're going to obtain.