>>1510662Because it is taxpayers plugging a profit gap on the tickets
Mass subsidies for national airlines and lack of taxation on tickets and fuel makes flying way too cheap, so cheap that HSR is not able to compete on many routes despite being far more economical. Its national governments protecting their airlines and a very strong flight industry lobby in Brussels. This situation has persisted through decades, despite the rail infrastructure being there. Many European (and US) airlines would go belly up without govenments injecting them with cash every year (and whenever the next crisis pops up).
Pic related; one of the many zombie airlines