The general argument brought around by "High Quantity & Low Quality" vs "High Quality & Low Quantity" is that, at some point days/weeks/months in the fighting, the Low Quantity that Quality started with will begin to hurt your ability to continue fighting far more as you lose more and more people/equipment in combat. Plus the simple issue that lower numbers of people/equipment can't physically be in lots of places at the same time, so you allow the enemy to stretch your forces too thinly or you condense your forces into less places allowing the enemy more room to manoeuvre against you.
The biggest issue the UK MOD (and a lot of "western" countries) has right now, is that they have virtually no "depth" to be able to accept large combat losses and replace them with an equivalent, because the mantra of "Do more with less" (driven by decades of Government spending) has left us stretched extremely thin, meaning resources (people/equipment) have to risked as little as possible by the military leadership as there's just no way to replace them once they're lost in combat (Afghan & Iraq are prime examples on a macro level) and there's the political risk that public support might drop once hundreds of dead/injured start coming home every week as expected in a peer/peer conflict, where the first 10 days will be a meat-grinder for absolutely everyone.
