Navaleye,
There will be times when HNS will not be available. In an ideal world you'd want carriers to 'cover that gap' - though carriers themselves will often require the same or similar 'consent' from neighbouring nations.
But when the entire Defence Budget is at breaking point, buying CVF and JSF is tantamount to spending money on a gold plated sand-wedge and scrapping every iron above No.6, and every wood in the golf bag in order to do so.
'With respect' the cost of CVF (and JSF), the huge manpower and support assets they require and the modest sortie total they can generate means that while they may be flexible, powerful and versatile, one thing they are not is cost-effective.
And apart from the Falklands, there have been no occasions when 'only a carrier would do', and where my 'fantastical bases' have not, in fact, been available. You say that "my argument that usable airbases can crop up anywhere in the world where and when we want them is pure fantasy." I don't pretend that that would always be the case, only that the occasions when bases will not be available (and when US/French/Italian/Spanish coalition support is also not available) are so rare as to make a UK carrier an expensive luxury. It's pretty persuasive that such bases have always cropped up, every time we have needed them, except during Corporate. We haven't even been put in the position of being unable to do something without coalition carrier support, had ours been unavailable.
You may think that regardless of cost, Britain should retain the capability to mount a Falklands type operation anywhere in the world, and that it should be able to do so autonomously. I do have some sympathy with that point of view. Indeed my own baseline would be the ability to do another Granby as well. I would probably vote for a party who embraced such a view as policy. But if that is your point of view, then you must be prepared to pay for it, and our Government is not prepared to do so. Nor is there much prospect that any Government will propose the kind of tax rises (or the diversion of funding from social programmes) that would be required in order to fund that kind of force structure.
If the aim is to provide the most useful, versatile, and cost effective forces to support coalition operations, on a more limited budget, then spending on carriers will too severely limit and constrain spending on more useful, more frequently required and more versatile assets.