I was a regular on Ryanair London Stansted to Tampere, fares looked good from Ryanair's point of view, it was always a couple of hundred £ return each, flights were always near full (sometimes 100%), no competition. Mainly Finnish pax, minority of British. Yet the route was given up a couple of years ago. They have maintained routes from Tampere to a few oddball other European destinations, but given up this one. It was even common to find Russians on board from St Petersburg, and the car park at the Ryanair terminal always in Tampere had Russian cars in it. Yet the flight's gone. They never tried London Stansted from Lappeenranta, right on the Russian border.
The airport authority at Tampere even made a special terminal for Ryanair, separate to the normal one, put into a converted hangar. As they only used to have one or two flights a day it must have been an extra expense to keep it going, especially as the main one itself always seems sparsely used. It still seems to be opened up for the few Ryanair flights a week remaining.