Well I think for a lot of people its access and probably childhood experiences. Certainly access is the reason I only got into anime 3-4 years ago. Streaming services allowed me to try this stuff.
And just look at the popular perception of US people refusing foreign content (especially subbed content). A lot of that would come down to what they were exposed to as kids.
For me in Australia we had a broadcast channel devoted to showing non-english content and so I was well accustomed to watching subbed shows and films.
Yeah that's a good point, we're all accustomed to what we grew up with, which is why you see such a huge disconnect between both the old and new generations.