As you say; the problem is that there is a thick growth of fuel - both brush and dead trees - in modern managed forests. I'm guessing that this is because for decades any fires that start up naturally have not been allowed to run their course, and because no artificial clearing has been allowed.
Fires in natural forests burns through the 'easy' fuel - brush and dead trees. The fuel pockets aren't thick enough to 'connect' over large areas.
But in a toxically-managed forest the fuel builds up and up - and the fuel 'connects' across miles and miles. Any fire that start in such a forest rapidly become vicious, fast, huge - and profoundly unnatural.
This is a great article - really thought-provoking.
Environmentalists have worked to ban livestock grazing from public lands for decades. Sheep and cattle grazing on forests and BLM land used to keep understory and dry grass proliferation under control. The bans on grazing have greatly contributed to the increase in wildfires.