Click on the github link you gave, click on his personal website,
https://russ.yanofsky.org/ that is listed there and the SSL is expired.
Which if you ignore leads to a really old school website that has not been updated in 15+ years.
If it means their focus is primarily on Bitcoin and not their personal site, then it's probably not a bad sign.
Besides, seems to be a trend these days that social media has now effectively replaced personal websites. Easier to update, more obvious engagement from others, etc. I'm pretty sure that's normal.
Agreed with 1 point, which was kind of my I made it. I have a lot of crap sites out there. I 100% admit it, a lot are not maintained or even looked at. But are still sitting out there, if you happen to trip across one of them so be it. If something dies on one of them like the letsencrypt renewal, then also so be it.
However, since the link was directly in his github profile I would think that he (or someone) would have noticed it an fixed it, or changed the link.
As Carlton said, more maintainers is better.
-Dave