You are paying five vendors to render one storefront. Every one of those five is a native feature of Shopify Plus.
Shopify Plus ships Flow and Launchpad on every Plus account. Low-stock reorder triggers, automatic restock alerts, coordinated promotional events that flip prices and theme assets across all ten showrooms at midnight, automatic builder-account approval flows when a contractor uploads a tax-exemption certificate. None of this is possible on the current NMG/Next.js stack.