Maybe the other person had no desire to participate.
This has been party season. I've lost count of the 'conversations' I've been caught up in where one person* did all the talking - and not because others were unable to get a word in edgeways! Silence is the polite way of telling one's interlocutor that one has no interest in the subject of the conversation. When a silence has lasted long enough it becomes fitting to change the subject. ;-)
* Yes K?v?n, I'm talking about you, should you ever find your way here.