The funny thing is, I don’t think LCD monitors have a very wide color gamut in the first place. They tend to stop far short of the level of greens your eyes are capable of seeing. A color gamut shows for all consumer-level displays, it can only represent 30% to 40% of the colors your eye can see.
LCD colour monitor gamut is a function of the backlighting that it is equipped with. Newer laptops use LEDs, whose emitted spectrum is better suited to display a wider range of colours than the ones equipped with a fluorescent tube-based backlighting.