It seems that mobile players can no longer be competitive...
It's funny you think this, because I've long thought that the mobile version is much easier than both PCEA and especially flash, and that the players on those platforms were at a disadvantage when playing against mobile players. I've come across quite a few mobile players who somehow made it to Champ level with an average in the 50's on mobile after less than a year playing. Sure, they could all be cheaters, but if they're sandbagging, it says something about the easiness of the mobile game compared to Flash. I moved over to PCEA about six months ago from flash, and I've found that some things are easier on the PCEA while some things are harder, but overall it's the exact same game and both require a ton of practice... And that's not even taking VEM into consideration.
As far as using the math... Why can't you use a calculator? Several mobile players use them and spreadsheets. If you want to compete with the top players, you'll need to figure out a way to consistently drop your approach shots next to the hole and improve your high putting average. Some of the top mobile players claim to do this by memorizing how far their clubs carry, but most seem to have spreadsheets and calculators. But even having the exact distances, etc, doesn't guarantee a low score. You'll also need to memorize the greens, become consistent with the meter, and learn how to deal with VEM when it kicks in because you're playing well.
I believe that for most of us average players, whether we're mobile, Flash, or PCEA, and whether we use math or memory, it all comes down to practice.