Most of the responses in this thread seem to boil down to "that's how it was from the start, so that's how it should be". I'm keen to understand why it was like this from the start. Did Satoshi (and other developers) not consider the impacts of lost coins and population growth?
I guess it was plainly out of the simple fact that Satoshi wanted to create a currency which is not inflationary. The creation of Bitcoin was a reaction to the failed features of fiat, one of which is its infinite supply, which causes its never-ending devaluation. Bitcoin was designed to gain value over time, not to lose it. Increase in users as well as lost coins must have already looked forward to by Satoshi and it should have been treated as contributory to the goal of creating a currency which is appreciating rather than depreciating in value.