He states that in his research, paved roads were in fact campaigned for by cyclist organisations such as the CTC
That sounds right to me, but their campaign wasn’t very successful judging by the contents of that old CTC route book. It gives a summary of road conditions for each route, and makes special mention of tarred sections, of which I can find less than a handful in the whole of SW England, whereas there are many sections highlighted as being in poor condition.
What seems to have ‘turned the corner’ for hard-surfacing of roads was the damage done by motor vehicles, the dust they threw up in dry weather, and the campaigns run by their wealthy owners. The AA had more voices in high places at that juncture than did the CTC, although I suspect that the CTC had far more members. Presumably the increase in commercial motor traffic after WW1, lorries and buses, was part of the story too.
PS: I don’t know whether the author you mention delves into this, but the term ‘paved’ has to be used with care. Nowadays we use it to mean something like sealed or hard, but historically it included loose paving as well, so a Macadam road was ‘paved’ with graded layers of stone, small gravel as the top wearing surface. There’s a section of ‘Macadamised’ turnpike reproduced at the Chiltern Open Air Museum, and it is a surprisingly good surface, one that would be lovely to cycle on, but one that would take a lot of maintenance to keep in good order under heavy traffic, and which would ‘cut up’ very easily with tractive forces through the wheel-road interface as opposed to through the hooves of horses.