I think that was the point of the 'ZF' comment. Whatever varien had as an ecommerce package before their ZF uptake was likely different enough from what Magento was that it's not terribly accurate or useful to say "magento's been around for 10 years".

Magento in its current form has been around for ~4 years.

Wikipedia even indicates that Varien was using osCommerce before Magento was developed, so they likely didn't have a full commerce stack of their own for the last 10 years.