Adding 15 euros to a 150 euro ticket will result in small loss of pax. Adding 15 euros to FRs 45 euro ticket will lead to a massive loss of pax. FR trades on generating demand by low headline fares. It had a low cost base as it could sell on 4-5 year old planes at around the cost it got them. With around 300 planes it is very much hurt by rising fuel prices hiting the other airlines.
It is going to take a lot of years for FR to sink but the whole firm is based on cheap oil and pax with lots of spare cash for a weekend in lubeck!
Ryanair trades on providing tickets for people who want to travel.
You are stuck in a time warp that assummes what happened yesterday will happen tomorrow rather than reinvention.