Realistically from what I've seen in Sweden, this isn't necessarily true. I'm sure it depends where you are going. I will be taking the night train this summer

Realistically from what I've seen in Sweden, this isn't necessarily true. I'm sure it depends where you are going. I will be taking the night train this summer to go into Lapland from Copenhagen area and the round trip cost for my ticket was about $235 USD which includes a transfer in Stockholm. Similar plane tickets were priced roughly the same with long layover in Stockholm. I suspect it will not be possible for the night train to ever beat a short haul point to point on a Ryanair bike seat halfway across Europe between two major cities. But for anything more remote the night train will probably be quite competitive. After all, the infrastructure already exists for the most part.