Shearer's record is incredible.
However, that particular stat is a bit misleading because he'd had getting on for three seasons playing as a starter in the English top flight, then called the "First Division", before playing in the Premiership. In other words, he had three seasons to get up to speed in games not counted as the Premiership. Foreign strikers like Aguero can arrive as pretty much the finished product, but the games in which they adjust to English football will be counted. To break Shearer's record, they'd have to start scoring on arrival.
100 goals in 124 games is an amazing run of sustained form regardless of whether those are your first 100 games or not. Basically unstoppable.