Comment by fatbird

It's pure economics. One large facility is cheaper in fixed cost terms than four smaller facilities. It's also cheaper in variable costs of staffing and other economies of scale like consumables. Lastly, the size of the large school means the cost of special features like a wood shop, kitchen, large theatre, art facilities, etc., are relatively smaller and thus more easily included in the whole package.

You're right that something is definitely lost. It's an externality that's forced on you and your children. There are compensations, but it's not an unambiguous win.