Climate change papers predicted 10-15 years ago that what average temp rises meant is changes in existing weather patterns, and that those changes would lead movements in weather streams that protected some areas from polar conditions... i.e. that rising temps weren't just hotter weather, but more variable and extreme weather... that 100 year events would start to occur every 5-10 years.
The Texas conditions are that.
But they're compounded by local policy on utilities seeking cheapest price for decades, and not investing in capacity or protection from extreme weather. So no regulation existed to force utility companies to ensure they could withstand extreme (relative to their norms) weather.
The Texas weather, similar to the UK "Beast from the East" recurrences, are predicted to now occur more frequently. So whilst from a historical perspective it is rare, it is now going to be more common.
Texas being so unprepared typically warm their homes on cool days with space heaters... electric heaters with fans... being just about the most power consuming heating available with no residual heat (i.e. stop running them and they don't stay hot)... so people run them constantly and that's overloaded a grid that doesn't have the capacity for it.
Oh, and they lead on wind power, more in Texas than in the UK (and our seas)... but they never opted for the few % more cost to keep that stuff working in cold weather, so it's all iced up and they've lost all of that power generation from the system.