Can Bitcoin really survive without an ever-increasing price? If it can't, it's a pyramid, because it does not generate wealth like most investment avenues.
Requiring ever-increasing price as measured in some other currency is not what defined a pyramid.
Requiring unsustainable growth rate which must eventually consume all of the available number of something limited is; most strictly, a pyramid scheme requires exponentially increasing number of participants at a rate that exceeds population growth (usually on the scale of requiring the entire population to participate in a very short period of time.)
To not be a shrinking role in the economy, Bitcoin may needs a long-term growth rate (once coin mining is exhausted) equal to the growth rate of the economy (which may or may not be always positive over the long-term, and if it is may only be logistic), but that's not a pyramid.
A pyramid scheme requires unsustainable exponential growth in number of new participants. Bitcoin can survive without that, so it's not a pyramid scheme.
> Said another way, why would anyone "invest" in Bitcoin unless there is an expectation that the price of Bitcoin will increase?
Investment being motivated by expectation of future price increases is not enough to make something a pyramid scheme. I mean, that's what motivated most investment in anything.