It could be that we have been fighting above our weight for decades. Successive Governments, Tory as well as Labour have cut the military budget.
The Argentinians invaded the Falklands when we cut our Naval fleet. We had to commandeer Passenger Cruise Liners and Merchant Container ships to get out of that cut too far.
When the threat from the Cold War and Northern Ireland terrorism diminished, that led us to downsize. When our troops were next needed, we weren't adequately equipped.