Depending on one provider or technology so deeply that leaving means rebuilding — proprietary services, exported data in a format nobody else reads, or a platform only one agency can maintain.
It removes your negotiating position. Price rises, deprecations, and service changes stop being decisions you can respond to, because the alternative is a rewrite.
We keep data in portable formats, isolate provider-specific code behind our own interfaces, and hand over complete infrastructure definitions — so staying with us is a choice you keep making, not a trap.