What defines a microbusiness isn’t necessarily that it’s run by a solo entrepreneur, or that it is a digital-only company. There are Mom and Pop shops, family run businesses, and million dollar firms that fall into this category.
The main determinant of what falls under the heading of microbusiness is size, according to the Small Business Administration definition.
(I believe it’s important for businesses that are solo-run enterprises that wish to grow to have a few employees band together with those who already do so. We so much to learn from each other.)