What are the plausible explanations for how strict lockdowns wouldn't significantly slow down infections for a respiratory disease? Is it basically just that th

What are the plausible explanations for how strict lockdowns wouldn't significantly slow down infections for a respiratory disease? Is it basically just that the lockdown strictness, duration, and enforcement is never sufficient to make a difference for such a highly contagious disease? Like there basically isn't a sufficient decrease in the number of person-to-person contacts to meaningfully change the end result of "everyone gets infected"? (I'm not asking about the other negative effects of lockdowns not directly related to the spread of disease, which is obviously also relevant to the broader discussion.)