One has to remove the emotion from the subject. Access to HE will suit some better than others, simply doing A levels will serve others better and there are other routes that serve others better. This is true from both the perspective of individuals and institution/course combinations.
The issue with the debate as I see it is there is no context. No doubt that depending upon where one is targeting to study and what one is targeting to study, either route maybe the percentage bet upon which to put your educational wager. The discussion about absolute relative merit / difficulty is irrelevent, all that matters is success rate in the different scenarios. So being able to quote that 1 or even 10 mature students had success using one route is meaningless without context. The context includes the individuals employment and pastimes, family situation, other qualifications already held, which ever route is taken. Quoting rare examples from a sample of 100s of thousands (> 1000000 if a few years cycles are considered), is for either route is misleading, and meaningless without context for the examples (which may be rare exceptions) cited.
(Avoiding route A as it may be associated with Access or A level.)
So for route B to degree subject XXX Y mature individuals applied to Super Uni Limited, Y/1000 received offers but for route C it was Y/50. Then you need to understand the context of the successful ones, especially in the former case, without context the whole exercise is futile and misleading.
Student Ms Anom, received an offer from Super Uni Limited and Very good Uni Limited, having followed route C and has just completed her Ecology degree. Excellent that is a plus vote for Ecology via route C..........but is it....... actually only 20 out of 2000 applicants using route C got offers for Ecology, and the individual referred to had been a member of their natural history society for 20 years, had published several documents on its website regarding local population surveys and local conservation projects, as well as having completed, 10 years ago, the 60 credit Open University foundation (L1) module in science and a (L2) 30 OU credit module in animal population dynamics and modelling, passed with distinction.
I have posted the link to the Data for numbers of mature students reaching Uni by course type and qualification route, in the Access - Applying for physics thread. This does not measure offers received but folks who start, i.e. they received offers that they could meet, no context available except disadvantaged postcode. Lots of other useful stuff on that site which , if analysed, might help an individual choose the correct route for them, factored by personal circumstances such as those indentified in earlier posts. The head line is that all routes are equally successful for Physical Sciences and mathematical sciences. In fact no route is dominant for these two subjects, what is very clear is that very few mature students either choose these subjects, and/or get offers they subsequently meet.
The issue is that most of these Access / A level / or whatever route threads end up as Canon V Nikon, which are equally unproductive if one is looking for information on which camera would suit you best.