He might take 40 days to complete a film, but his team plans everything perfectly for him so that he doesn't waste the producer's time or money. He has done this for 30 years and churning out 4 films in a year is normal for him. So for him to slow down and do lesser films is too much of an ask.
And quality of his films, he has given films like Baby, Special 26, Good Newwz, Kesari, Holiday, Airlift, Rustom (I found this okayish, but was appreciated well). I don't see the point in taking years to complete one film when another actor in the same industry can finish films within 2-3 months.
And if people say that the scale of his films are smaller, then look at Housefull 4, Sooryavanshi, Prithviraj. These are also big scale films, and were completed within 3 months (Prithviraj would have been completed had it not been for the lockdown).
Infact, I read somewhere that the longest he has ever shot for a film is Rowdy Rathore at around 75 days.
So he is in the best phase of his career now and while Bell Bottom is shot within 40 days, but what has to be appreciated is that even in such tough situations, he has made his producers and other workers happy by doing the film. I have heard the teaser will be out soon, and the film being a spy thriller with a hijacking theme, I am expecting something like Baby or Airlift from this film. Footfalls will not be high as it's not in the regular commercial zone, but if well made, it can turn out to be a great film. And as a fan of Akshay and of thrillers, I can't ask for anything more! :)