I mostly agree... I used to work for a classic car website, and in that case, we dealt with a LOT of comment spam, and scams that were out there. A lot of it is actually individual people, doing actual work to get past. We also did see a lot of custom bots, etc. It took a few different approaches and even recaptcha wasn't always the best option, but it did help with most of the non-scam traffic.
This is as primitive as it gets. I didn’t get a single spam mail in all that time.
The idea is not to outrun your competition, it is to become a special target that would demand special work to successfully get into. Bots are dumb as long as the humans behind them don’t give them a hint how to deal with your site.
And if you’re really that valuable of a target, you can step it up a notch or even switch to google’s data collecting solution.