There is cost the individual user of an open source project has to consider, and there is cost the community of that project as a whole has to consider.
So from your perspective, just keeping the old version might be "the right thing to do", and at the same time the decision of the community to not support it anymore is also "the right thing to do" from their perspective.
As the community does their work unpaid, it seems you have no right to impose your perspective on them, except if you pay money for the necessary work. Which you are free to do.
I guess what the parent posters point out is that this will usually shift your own cost/benefit ratio in a way that upgrading becomes "the right thing to do" for you, too.
It seems to me that all counter-arguments I get ignore the context that I set which is to not do things "simply because you have the money".
What I get is "hey, you have the money and it's obviously the right thing to do so do it".
"Having the money" is orthogonal to "it's the right thing to do" but this thread is too old to recover.