Wet bulb events aren't that simple to deal with. Grid stability doesn't exist in any of the poor and hot equatorial countries. Many people don't even have airtight housing which rules out aircon. If it was too cold instead they could just add clothing and blankets and survive.

Grid stability isn't necessary. It's OK to only run air conditioning when the sun is shining.

There are often blackouts while the sun is shining in lower income countries.

Yes, local solar panels are needed too.

It's cost prohibitive, a small hybrid system costs $4000usd which exceeds the average annual income of many equatorial countries. But you are right that if somehow everyone could install this system (along with an AC and the construction of an airtight room) then wet bulb events would be manageable.

The solar panels to run an air conditioner are a similar cost as the air conditioner.

What difference does it make if heat leaks out or in? The transfer rate is roughly the same.

You can't install aircon into a shack. The cold air will escape.

What happens to heat in a shack?