Sometimes a comment with lots of upvotes is still obsolete and should be removed. This is usually the case, for example, when it requests information that the OP then provides (and provides in such a way that it's clear what information is being provided). There are other situations as well where this makes sense--for example, if the information it contains is fully integrated into the answer, or when the commenter asks for it to be marked obsolete under some circumstances and then those circumstances come to pass.
However, sometimes comment upvotes don't just express voters' views about how well-written or technically correct a comment is, but also express subjective agreement with a well-articulated opinion the comment expresses. Or, agreement with a course of action the comment describes. For example, in this question, adempewolff commented about contacting a hardware vendor to get information pertinent to the question, which itself is potentially of great interest to a large number of Ubuntu users. This course of action (which adempewolff took) is both proper and admirable, which is probably why that comment got five upvotes. Since then, the vendor replied and detailed information about their communication has been prominently added to the question. So this comment is obsolete. But the upvotes express some measure of community agreement with this course of action, so arguably the upvotes themselves are not obsolete and the comment should be retained.
On the other hand, since comments are "second-class citizens", surely their upvotes are even more peripheral to the operation of Ask Ubuntu. So arguably no comment should ever be retained on account of its upvotes.
What's the best course of action here? Would it be right to flag this comment as obsolete?
Please note that a "no, keep the comment" answer here should not commit us to keeping all comments that express good ideas, and which are upvoted by the community. For example, if a comment says to provide hardware details missing in a question about boot problems, it can probably still be removed (after the information is provided) no matter how many upvotes it gets, because experienced users of Ubuntu are already very mindful of the need to provide and request this information. On the other hand, realizing that sometimes it's important to contact a manufacturer of (existing or future) hardware to figure out if/how it will work with Ubuntu is something we're not always as mindful of. That could be taken as a reason to keep this and a minority of other comments expressing subjectively good ideas, without having to keep most such comments which turn from valuable information to clutter over time.