25 years ago the grid didn't have phasor measurement units, distribution-level sensors, internet-connected SCADA systems, smart meters, demand-side management,

25 years ago the grid didn't have phasor measurement units, distribution-level sensors, internet-connected SCADA systems, smart meters, demand-side management, or even computers very much. Now all those things are commonplace, and they make the grid much more stable in a world of stochastic supply. (Some of those things also make the grid a lot more vulnerable to black-hat hackers, but that's another subject.)