Low cost airlines have been big in Europe for at least 10 years before Airbnb started to become common around here. Before Airbnb, budget travellers would usually stay in hostels as hotels usually catered to business travelers so were much more expensive. Hostels only really became popular due to Hostel World so maybe they should take the blame :D
It's a little unfair to point the blame solely at Ryanir. The Spanish flagship airline, Iberia, also has a low-cost wing: Vueling, based in Barcelona and established in 2004.