It really isn’t that hard to tell the difference between bots activities and humans. If Facebook can detect a nipple in a picture in microseconds they can tell that “hmm a surprisingly high number of IoT fridges have strong opinions about this anti-Putin blogger, starting last week” isn’t valid.
That sounds like the millions of doctored amazon reviews and social media bot-boosted content should be dealt with by next week then.
If there was an incentive to do so there would be.
Alphabet doesn’t have real competition. If they start getting some they will be motivated to improve. Amazon the same way. You order crap from them and they still make their money. Social media the same way, there is just no particular reason for them to anything about bots when bots don’t impact ad numbers.
The corporation I work for has a captcha on the website to do pretty much anything useful. We have an incentive to not have bots.