Actually (pedant mode on) it's been a lot worse than decimation.
In 1984 we spent 5.5% of GDP on Defence, now we spend (after some accountancy fudges) 2%. Each aircraft is also, proportionately, more expensive than those of the 1980s. So it's hardly a surprise the front line is radically smaller than that of yesteryear.
So what should our current leadership do? I suppose they could just sit on PPruNe and winge about how life is so unfair, but I far prefer it that they try to articulate how they intend to build a future with the resources they are being given.