Not in my experience. I see it almost every time I end up in a reddit thread from search results. I've recently started demoting it in Kagi. It's just not as good as it used to be. Newer threads tend to be full of junk and bots.

I see it quite often in reddit threads that appear in my google search results for obscure technical/hardware issues.

The original helpful comments were probably provided by switched-on users of whatever subreddit, and those same users are the ones most likely to nuke/overwrite their comment history when they leave the site.

Please provide data on your claim.