This neither is nor has been true, and it's certainly not a desirable goal.Only they aren't (though one can see why a lifetime Regular might think that they might be) they are selecting those young people who can afford (gambling that they will get through as if not they will be out and their pay stopped) to take a year off or 'out', often post education before starting full time employment, together, of course, with some sectors of self-employment.
There have always been a number of Reserve units and individuals that don't quite fit the normal "Reserve" pattern and are much more like part-time regulars or regular part-timers. SAS(R) are clearly one of them. It makes no sense to invest that much in anybody for a cursory return of service.
Dropping the idea that they fundamentally need to fit everything around a 9-5 stereotype, and instead self-selecting for those who will commit more time more flexibly, for whatever reason, is very sensible and should have happened earlier.
Again, this seems designed (whatever the blurb is saying) to limit the direct entry route. Which, again, is sensible if the goal is to have a more professionalised, semi-regular unit. It's always been a bit of an oddity that 21/23 were the only ones who allowed direct entry to SF without some prior experience.The official wording is: "Applicants with no previous military service will be sponsored out to their recommended local AR unit to complete basic training and gain experience before being allowed to attempt SAS Reserves Selection."
If you contact Them (R) off the street you will be sent to a local AR unit and can be loaded on BAC once you have completed training. This has only been in place for just over a year, it will be interesting to see how it pans out but I expect some units will get rapidly threaders with it and especially picking up the pay bill for them though Aptitude and SOPTAC.