The competition is only one factor that contributes to how popular NASCAR and F1 appear to be. Outside factors, like those listed below, mean that attendance numbers can, and do shift, and shift often. It’s hard to look at the comparative attendances for any one year and say that one is more popular than the other as a sport because in the next few seasons, that can all change. - Host venues - Ticket prices - Race rules (in particular changes to race rules) - Car shape and engine works (changes to these) - Additional entertainment - Streaming times and TV rights - and in recent times, COVID-19 Both categories of motorsport have seen modifications of rules and regulations over the history of the sport that can have an impact on fan engagement and directly impact the enjoyment and popularity of the sport. For F1, getting access to international races on TV anywhere in the world is easy enough with detailed coverage across a number of big networks and, to an extent, time zones are factored in to be convenient to as many counties as possible. As social media rules are relaxed F1 is also being made available across a number of more casual platforms as well, including the occasional YouTube uploads, previously disallowed through tight copyright enforcement. With NASCAR, being a US-based sport, getting access outside the US to watch and stream can be more difficult, unless you know where (and when) to look for race coverage it can be almost impossible to view a race live. It begs the question of how much more popular NASCAR would be if a worldwide audience had the same accessibility to footage as F1 fans do.