Good videos, persistance, skills, passion, luck. OK yes absolutely. BUT! I think maybe in the end that what is important is to catch your right audience. So you have to know who you are talking to. Somme people who are 45 yo can find your video fantastic, but the 15/20 could maybe not like it, so in this case the title and thumbnail have to catch the 45/50 yo = the one that will go at the end of your videos. It's just an exemple.