I would prefer to see a greater emphasis on the creation and maintenance of a mosaic of habitats around the countryside, rather than this one (alien?) species being the focus of so much time, money and resources...blah blah blah.
This is more or less what is happening, at least here in Somerset. There are at least six large-scale habitat creation/linkage projects taking place, three of which are aimed at butterflies, all of pretty similar scope. In the Poldens, habitat for the Large Blue, but also for Chalkhill Blue and Duke of Burgundy; in the Blackdowns, for Duke of Burgundy, Wood White and Marsh Fritillary; and on Exmoor, for Heath Fritillary. Except for the Chalkhill, all of them would be extinct in the county were it not for long-term efforts to maintain the few pockets of habitat in which they survive. I'd imagine this is true of most of these species nationally, as well.
On a different subject, what makes the reintroduced Large Blues a separate subspecies from the extinct ones? They are functionally the same - having the same lifecycle and emerging at the same time when put on the same sites - and are not as far as I can tell visually different. Yet, amongst the extinct butterflies, Cornish Large Blues were obviously not as dark as Cotswold ones, but the two were not considered different subspecies...