yes and no
Micropresses are even smaller than small presses, and have less ability to distribute and market your book. Small presses don't have the budgets of med or large ones, but they still manage to do a fair bit of promotion. Micropresses don't.
Micro presses are smaller than small presses. They usually tend to target a smaller audience than would be profitable for most publishers.
For even a micro press to succeed, they have to do promotion. Some promote to their authors, placing them in the vanity press market. Others know how to market to their niche customers.
Micro publishers often use non-conforming methods to sell books. Some will filter into bookstores. Most will have a niche market to tap through industry magazines, newspapers, or other publications where the niche goes for information. They may also target conventions, conferences, and speaking engagements. Sales will not equal typical commercial ventures, but success can be achieved on a smaller scale.
No matter the size of your publisher, they should know how to sell your books. Otherwise, why not self publish?