Good points, Leon. I think the transition we're witnessing is a shift from film based photography being a mass medium (family snapshots, fashion photography, press etc) to an artists' medium. In this modern day and age, you can still buy oil paints, watercolour paints, pastels etc even though the market for these items is relatively small. The introduction of acrylic paint materials certainly cut into the oil paint market, but didn't kill it simply because the convenience of acrylic paint comes with trade-offs. Some artists just find oil paints to be more appropriate to their work or way or working. Digital photography has some advantages for artists as well as the family photographer, but there are obvious trade-offs and film will continue to be the choice for many artists.
As far as growing the market and websites like Polanoid or LSI are concerned - I generally curb my enthusiasm for these. I think its great the sites exist and showcase film photography, but I also think the reality is that of every 100 people new to film photography who get enthusiastic from visiting polanoid or LSI and buy a camera and some film, 99 of them will not purchase additional film once they've shot the first batch. So unless several million people are visiting these sites a year, the sites are not growing the film market to any measurable extent.
Paul