That is pretty reasonable. But from my perspective (and don't think I'm trying to justify it, I know you're not launching an attack on fans), I was working on Thursday until 5:30, so I would have had 15 minutes to get to the airport, get a flight, and get to the stadium.
Add onto that the fact that I've got to book £450 flights to Florida on payday as I'm going to a festival there in October, it's not affordable to also go to Austria.
I think most people are in similar financial situations. This sort of time, when people go on summer holidays, and in the run up to Christmas, most people have pretty much no money.
If we've got any European away days after Christmas, expect the support to start increasing.