Current SMR designs are absolutely available at substation scales. The reason they can be used this way is that they are high temperature systems that can be placed anywhere.

The whole reason that cold-war era nuke plants had to be so big is that they were lower temperature designs with very particular requirements for cooling that restricts where they can be sited. So they have to be able to serve large regions.

"Mass production" of SMRs need not be the scale of consumer electronics to be cost effective. Unlike a cold-war scale design. which must be engineered on a bespoke basis, an approved SMR design can be replicated over and over. Which is absolutely a more cost-effective production model. Versus the comically and unpredictably expensive cold-war model..