His response was that sometimes messages get lost because so many other things have come in to deal with. At the time (almost 20 years ago) this didn't make sense to me but, on the practical side, I did find that a follow-up message would generally get the conversation un-stuck.
Over the years I have tried to respond to the humans I want to communicate with but it continues to get harder. It seems that the situation Linus got himself into so many years ago is common. And the marketing response to that is to SPAM you (even for stuff you have requested to be informed about) on a regular basis. The result is that we all get more email and more email ends up lost (as in buried among other messages).
I have separated out some of my messages. For example, systems administration messages don't end up in my regular mailbox. The result, however, is that I have to look in more places to keep myself up to date. And the volume in my regular mailbox is still out of line because of all the repeat messages.
Is there a solution? Probably not. I was thinking about asking Linus if he has one but I would probably have to send my message 20 times before he would see it. :-)