I'm not selling/wouldn't know about Turbex, but you can bet they are slow and last just like the old pumpers did... 50 years on they still are running. I'm finally doing some maintenance on some 60 year old ones. They still pump every day in a marine environment..... even the fencing wire doesn't last this long.

Electrical systems are bad enough in remote places, electronic systems are to be avoided if possible.

If you could get reliable water for 3000 people for $70,000, and have no ongoing upkeep or problems or down time.... then this is an extremely cheap system...
If you have a messy system which is not instantly understood by a person sent to fix it, it won't be fixed. You may start with the right personal in place to get it to run, but people move, or die, and if no replacement is there to tend the network of small windmills and electrical and electronic gadgetry, then there is no future in it.

And yes I am currently designing a 3ph motor drive system, so am in favour of your idea from an experimental perspective, but not in the lives of simple folk who just want reliable drinking water, and don't much care how they get it.

The wind power over a year (if you can store it succesfully) is well in excess of the average wind speed x windmill output figures. The cube law for airspeed/power shows that the power from above average winds is much much larger than the power in the below average wind speeds.... which all go to makeup the average.

So the pumping figures you show are below what we should expect for that average site..... if you can use it all as it comes in.
So if you get a decent blow that pumps 3 days worth of water in a day, the big pumper will do it. How will the network of smaller ones with fixed upper boundaries do.
eg. If we pump a days water at 5ms on an "average day", and your system is designed around this.. next day when we get 10m/s, the pumper might pump 8 days of water, because it can utilise the 8 times the power in the twice average speed.
What will the electrical system do.
If in the next month we get a day of three times average speed 15m/s we can expect to pump 3x3x3=27 days of water. What will the electrical system be doing with this unusual extra wind?... and there will probably be a few days of it with a weather pattern of this type. In the real world, the figures would no be so nicely extrapolated, but you get the idea.

Any system that requires dump loads and furling to protect the alternators, will not take advantage of this fact. Strong winds will be dumping or the mill will be furling. The water pumper just pumps more water, (will furl in extremes), but not just strong winds that would furl a small wind generator. In other words the pumper can more likely take advantage of the strong winds where the real power is, general rule is that the small electrical mills will all be in furl and/or dumping if the batt bank is small.

I only use smaller(5'-8') wind pumpers, so this may all be nonsense in the bigger machines, but I'm sure a call to Turbex will get some info, and I notice they publish customer names to contact.... might be a worthwile exercise.

But thats how it works for us.