This is not such a bad analogy, actually. I think you point out that having a small number of customers can lead you to necessarily being a bespoke shop:

The fewer customers a firm has (some firms rely on a few very profitable customers), the more generalization you need.

You mean specialization here, right?

If you have ten customers, you must treat them all different[ly], or someone else is going to take them because they do.

Anyway... There is another side to market segmentation, and that's how many distinct products you provide. Continuing with your metaphor, I would suggest that I have one product (me) for the SMP. It would be wise for me to engage in some market segmentation, to be sure, given this state of affairs. I need to promote/highlight different things about me for different market segments (women). But, I do have to bin the consumers somehow, or I'm a bespoke shop for myself. To be that, I would either have to induce multiple-personality disorder in myself and be a master of disguise or just plain lie to everyone. That doesn't seem useful.

So, I do play up certain parts of me and downplay others, depending on the market segment. I play up my science PhD to nerdy girls. I play up the fact that I was a college athlete to other girls. I stress [pick a hobby] to others. I let my quiet nature take over in some situations, but try to be boisterous and loud in others. All good.

But, I have a limited number of degrees of freedom to tweak. Finally, it comes down to me figuring out what things I can make the "base product" and which "add-ons" I need to add in certain situations. This is a very common strategy to take advantage of market segmentation. I related a list of "add-ons" in the previous paragraph. AWALT forms the design criteria for my "base product."