Complex sentence: Because none of the Majors were played on hardcourts in Laver's era, Laver never won a Grand Slam tournament on hardcourt; this is quite different from the modern landscape, where half of the year's Majors are played on hardcourts.
Split into simpler sentences: Because none of the Majors were played on hardcourts in Laver's era, he never won a Grand Slam tournament on that surface. The tennis landscape today is different as half of the year's Majors are played on hardcourts.