The list of why a few million people stop flying ryanair would be very long but there are always new pax to replace them. The probelm is FR needs millions of extra pax par year and that means they have to do a lot more than replace those who stop flying with them. It is not that they will get say 10% less pax but they may get 10% less pax per plane. They are going to have around 300 planes which means thay will need about 90million pax per year to get 300,000 per plane per year.
The bad press the FR gets will not help, for example in todays papers about a childs accident on Ryanair.
Ryanair review urged after child falls while boarding plane | Business | The Guardian
Is that it ?????????????
Your own claim is that only 15 Million people fly them a year and now a few million will stop flying them BUT aside from a story which relates to incorrect supervision by a parent and is down to aircraft design not an airline you have NOTHING else.
You still haven't told us why you are no longer with them.