Better computer programs along with protection devices (the humongous equivalent to the devices we put to protect our home computers, to protect against power spikes) were installed.
When the man-made Northeast Blackout of 2003 hit, it was the result of a cascade failure that took down all the power grids of the northeast corner of North America. All of it? No, the province of Quebec (with its brand new protection) avoided the propagation of the cascade failure though its power grid.
So, it would appear that some places are protected while other are not. You'll have to ask your own power company.
---
What would failure mean for people on life support? The same thing that a failure would mean today. Power failures do occur, you know. We don't have to wait for the Sun to cause it (the 2003 blackout was caused by failure to properly clear trees around a high-voltage corridor).