This is some really awful math to be posting at midnight on a Tuesday, and it's dumb for a lot of reasons. The first is the concept that TRS balances around just the pub stats, which we know not to be true. Most of the balance changes typically revolve around A) a noticeable overbalance in pub stats, B) complaints from the pub user as to what's unfun and what they'd like to see, and C) advice from the pro circuit on what's broken and what's abuseable at the top level. They're on record as saying they don't just look at numbers, they also view feedback from players on their own forums and if they don't see both player feedback and correlative stats, changes are less likely to be made.
But the second problem here is that it's a bullshit premise in the first place. You don't know the frequency at which fast games occur, nor do you know the frequency at which long games occur. We can definitely assume that most games end at Stage 2, where hunters and monsters are smack-dab in the 50% column, because the first Evolve is easy and that's how the game generally plays out. Fast games are outliers, they aren't going to substantially skew that overall result, any more than long games. And personally, I think there are way more long games than short ones, which would skew that BACK towards the median line. There's no evidence to support your made-up hypothetical 2:3 ratio exists.
BUT ALSO. The monster win rate for Stage 1 games is roughly between 10 and 20 percent - I believe the highest I've seen listed was 18%. The hunter winrate for Stage 3 games is closer to 25%, which means that, assuming the bullshit premise that an equal number of games end in stage 1 and 3, hunters win more Stage 3 games than monsters win Stage 1 games and again it skews towards the median. Which is probably why the devs tend to balance towards 15% and 75% ratios in those stages respectively.
If you want to see the stats, you should probably start by asking about them at the Telemetry and Game Balance Thread, where TRS Chris Ashton answers questions every weekday and posts stats that people ask for. You should probably NOT start by making up a conspiracy theory and disseminating it on Reddit, then challenging the devs (who, with the exception of the head writer, have NEVER commented here) to prove you wrong because it's a semi-popular opinion that they're incompetent and you'll probably get upvotes.