If you go to /r/WooCommerce you'll see growing pains and that people are not happy in general with WooCommerce and plugin developers have to work extra hard to support ever changing WordPress.

There is a need of stable (not frequently changing) e-commerce app that can be hosted and supports stripe/PayPal and "shipment tracking".

WooCommerce requires yearly payment for shipment tracking.

When discourse is available for free, there is no reason why WooCommerce alternative which can provide more out of box support can't be free.

Today what options people have? WooCommerce, Shopify (SaaS) and legacy apps like Magento, Presto, Opencart.

This is not enough - most e-commerce development happens on agencies selling their services. We can certainly provide more out of box features with help of open develop model.