A decision was probably taken to wait and see what the effect of the new anarchic strips might be on sales before the Dandy tried to catch up - but it may have been too late by then.
A couple of notes:
Big Brad Wolf had a couple of 6-week runs, the second about a year after the first.
The last sales figures mentioned here on the forum showed that in that quarter, all three titles' sales had declined, but the decline in Dandy sales was rather less than either of the other two titles. The previous quarter, Beano Max was selling twice as many as the Dandy, and the Beano was selling twice as many again (ie 1:2:4) - that quarter the ratios had switched to 1:1.5:3 or so.
In terms of Adventure strips per se, I think it is fairer to say that the weekly comics had largely dispensed with them by the late 1970s with the final Whizzers from Ozz, Billy the Cat and General Jumbo, only Black Bob holding on until Albert Barnes retired. I don't really group Brassneck, Jack Silver and Winker Watson in with them, because although they were serials with an overall theme (eg Sneaky's special remote for Brassneck, any one of Captain Zapp's schemes to take over Marsuvia, or the Three Hoods), each episode was a self-contained comedy within that theme.
The annuals kept them going far longer - the Dandy featured one or two pure adventure strips into the early 1980s, we have already discussed Our Sheriff's an ape in this thread, and I think the Topper also kept them going.
