To weigh in with a bit of personal perspective:
I've been a member of the online community since the late 1970s, when I started using computer BBS systems with a 300-baud dialup modem, and I got online with what's now called the Internet back in the days when it was still called ARPAnet.
In all that time, I've never used any BBS, UseNet newsgroup, maillist, forum, listserv, or any other online community that stays 100% on-topic. Even the moderated forums I use, where every post must be approved by a forum moderator before it goes out, don't manage to stay 100% on-topic.
Any forum has to strike a reasonable balance between the purpose of the forum and the inevitability that conversations don't always stay on course. A forum that strays too far risks becoming irrelevant, but a forum that tries too hard to stay on one topic often ends up feeling controlling and unfriendly.
I don't always read the off-topic threads on TechSurvivors, but I do read some of them,a nd i appreciate that they add value to TechSurvivors by encouraging a sense of community and the feeling of openness here.
I don't think it's realistic to say that TS posts should always be on the topic of Mac troubleshooting; I don't think it's realistic for any forum to stay on-topic 100% of the time. I *do* think it's realistic to seek a balance between on-topic and off-topic posts, but I don't think that balance has been crossed as it stands right now.