Time is money, so I don't think trains can ever compete with flying for long-distance travel (>1000miles). They could do like the USA does and make flying such a time-consuming pain in the ass that it's rarely worth it for trips under 5 hours.
I can hop in a train at Zürich main station in Switzerland and be in Paris in 4 hours or I can get in another one and be in Milan in 3 and half hours. On my trip I can use the internet, go to the restaurant or relax in the quiet carriage. No turbolance, no weather delays and the ride is very quiet. How much work can you really get done going via airplane? How much time do you waste going through security and how well…
Europeans think that 100km is a long way while Americans think that 100 years is a long time.