it's definitely challenging for groups to maintain hit after hit over several years, and it's difficult to even get one for a lot of them
what groups have had several #1 hits in a row? is it a lot? is it only a few? does it vary by generation? it seems like there's an expectation for groups to never do poorly or if they don't chart in the top 2 or 3 they might as well have flopped completely.
what number of groups have actually done that???