Indeed, in the past controlled burns were more common than today. But they remain a management tool along with closely flayed fire breaks. But they are not popular with many people...
People tend to forget heathland is a man made habitat first created thousands of years ago. We don't harvest the gorse much for firewood (great for baking ovens). Heather isn't used much for roofing nowadays either.
There is now a huge backlog of combustible material and when this goes up you see the results, like in this unusually dry summer. The same thing occurs in places like California and so on where fires have been suppressed until the inevitable happens, a mega blaze usually started by a human.
I've also heard it suggested that these current outbreaks could be likened to a form of economic warfare. Hybrid warfare if you want to go down that rabbit hole. It's been done before to weaken an enemy. Today it costs the fire service and thus the taxpayer a lot of money to put them out and maintain the firefighting machinery.
Vale of the Great Dairies
South Dorset
Elevation 60m 197ft