Cost comparison at $5M GMV, which actually wins?

Sales volume alone cannot identify the cheaper store. Price the same catalog, checkout rules, payment providers, regions and integrations on each platform. Separate implementation from recurring software, processing, apps, hosting and maintenance. Magento Open Source has no software subscription fee; Adobe Commerce is a commercial offering with deployment choices. Shopify costs depend on the plan and payment setup. A useful comparison comes from current quotes and your operating requirements, rather than a universal GMV threshold.

Official references: Shopify pricing; Adobe Commerce pricing.