Total cost is an operating question.
Initial implementation cost is only one component. Include licenses, infrastructure, integrations, data migration, customization, security, accessibility, support, upgrades, vendor coordination, internal ownership, and the cost of changing direction later.
A lower launch cost can become expensive when the operating model does not fit. A more flexible solution can also become expensive when the organization cannot govern and maintain that flexibility.
Prototype the riskiest assumption.
When the decision depends on a critical integration, performance requirement, editorial workflow, native capability, data model, or governance constraint, test that uncertainty before committing to a full implementation.
The purpose of a proof of concept is not to impress stakeholders. It is to reduce a specific decision risk with observable evidence.
Document the exit path.
Before selecting a platform or architecture, understand how data, content, code, integrations, and operational knowledge can be transferred. A system becomes strategically dangerous when the organization cannot explain how it would change, replace, or recover it.