Solar and wind are fantastic, cheap sources of power, but they have their limits. They generate power when the sun shines and the wind blows, which is not necessarily when humans need it. We still aren’t very good at storing this power for use later, at large scales, in cost effective ways. So for now solar/wind needs to be paired with power sources we have greater control over, which mostly means nuclear, coal, natural gas, hydro, etc.

By the time we cover all the daytime load with solar, they will probably have better batteries though.

By then we'll probably have figured out fusion too.

And PV is now off the bottom scale of that chart.. Some combination of overbuilding PV and Wind capacity + ever-improving battery tech "won" the energy market. Gas peakers and other stand-by sources will contribute for decades to come but when they're pricing out new nuclear builds at >$0.10/kwh wholesale, no amount of "but capacity factor!" will matter.