You are wondering how many entities offers all-in-one online store. Well there are too many entities who offers all-in-one online store. The list will never ends.
The first in the list is WooCommerce. If you have ever heard about WordPress, consider WooCommerce is an add-on. This add-on will give the possibility to transform your blogging website to an online store.
The very things to consider is you need to add additional plugin, some are free and some are pro version.
Shopify is considered the fastest solution to setup an online store. It is a proprietary software, close source code. Used by many sellers because the platform unifies all you need to sell online. Still the need of plugin or add-on exist.
Shopify is hosted by company who owns it. No need for upgrade from your side.
Shopify is the fastest solution.
WooCommerce is always for someone who loves to make things different and distinguish him from the other by modifying the source code to fit his needs.