I would say that sports betting is both skill based and luck based. It depends on how much time you put into researching teams, players, coaches etc. You need to know the sport inside out in order for it to be successful. The more research you do before placing bets, the better chance of winning.
Good research will increase the chances of winning, but in many cases, even after good research, it is not possible to win there. If you have to lose to a relatively weak team even if you are on top of the points table, then no matter how good the research is, it is not effective. That is why neither experience nor good research is effective if luck does not favor it properly. Luck should be given priority not only in sports betting but in any gambling. However, although research is effective in sports, in casino gambling you have to rely on luck.