Like I said it's just my opinion and
"you can do as you like". I'm not going to stop anyone from posting to an old thread. My suggestion still accomplishes what you want though, just start a new thread like this:
"I was reading this old thread and it reminded me of an experience I had myself...."
This connects to the old thread but still respects the people who are no longer here and can't reply to whatever you post. I will say, a long-time member who participated in the old thread and now has some additional information would be different from a new member digging up old threads to bump.
I've been moderating forums since 2002 and this has been a relatively universal principle on most sites that I know. Regardless, I certainly don't want to discourage new members from sharing their experiences!