The evidence from the London Chess Classic is that the right event can attract an audience. The Classic is assisted by the tournaments running alongside, but the audience also comprises "people who used to play chess".Rob Thompson wrote: How many of the general non-chess-playing public do you really believe would go in and watch?
Seeing the pictures of the room in Simpsons reminds me of the 1973 European Championships in Bath. Probably helped by being one year after the Spassky-Fischer match and a chance to see well known players such as the Soviet Union's stockpile of ex-world champions in the flesh, the event attracted visitors in numbers never seen before. The venue was acceptable if the matches took place in private, but was overwhelmed by the numbers who turned up as spectators.
I think we have to accept that this first Agon event is a prototype. Whilst the internet coverage of the Tal Memorial and the Anand-Gelfand match earlier in the year was objectively better, they didn't seem to have much live spectator capability either.