Only an idiot wouldn't agree that Fed is a better player now than before, hence agreeing with Pat Cash.
The only problem is, opponents now have gotten to the same level as Fed, the natural progression of tennis and tennis players, plus Fed is choking now, knowing that every match is only getting tough for him, that is why He isn't winning anymore despite of being a better player than before. Also He has won more than anybody, so his motivation and desire isn't the same as if HE hadn't won anything.
Fed will never win another major, He is done, people think that because Sampras won another Fed will as well, this era is 1000% stronger than Sampras' and the margins are very small, chances that Fed will have to compete and win 3 straight hard matches at his best are very little.
Fed is done, whether we Fed fans like it or not.