You changed the platform. The problem came with you.
I want to say this as plainly as possible because it is the finding that arrives most consistently in ecommerce commercial assessments and the one that is most consistently absent from the business case that preceded the platform decision.
The commercial problems driving the migration were not platform problems. They were process problems, operating model problems, data quality problems, and team capability problems that were sitting on top of the platform and using it as a convenient explanation. The platform was the most expensive and most visible variable. Changing it produced enough motion to justify the cost and timeline in the short term.
Twelve months post-migration, the conversion rate is within a rounding error of where it was before. The product is faster and cleaner. The capability is genuinely improved. The operating logic that was producing the commercial underperformance migrated with the data and the catalogue and is now running on a better platform.
Technology is a shop fit. The most beautiful shop fit in the retail park does not save a buying strategy, a staffing model, or a customer experience that is not working. The customers can see the difference between a good fit and a good shop.
Related reading