No, my fault for wording my posts badly I suspect!
Regarding your last sentence, there is a huge wealth of data on healthcare, it spans weekly performance data in individual hospitals to national data gathered in 24-month cycles and everything in between. To an extent, it's probably too much data - you can count just about everything in healthcare but bridging that gap between those different forms of data and turning it into meaningful and purposeful allocations of resource is a Herculean task.
With regard to your first sentence, the point I was trying to make was that if you tried to introduce a new form of council tax, rates or local income tax, it would be a mammoth exercise that would require huge resourcing across central and local government. Likewise any piece of work to change or restructure how healthcare is resourced.
There has been an erosion in capacity within central and local government over the last eight years due to 'austerity' or whatever we choose to call it. Brexit has taken up a massive amount of what was left, with civil servants removed from their substantive posts to work on the sheer volume of detail involved in leaving the EU. The actual practicalities of trying to reset Barnett, at least in my opinion, would be a huge ask of an already depleted workforce and were it to be done properly, I don't think there's the adequate resource to do it properly while there is so much flux in the system.
The ONS and the likes of the General Register Office are important in providing projections, but the planning and implementation work still needs to be done by people (and the ONS and GRO are only making projections, based on pre-existing evidence and reason-based assumptions)