DW Architecture for Special requirement

Hi,
We have a current DW/BI system that enables BI reporting and holds data for 2 years. We have a requirement from a special user group requesting to extend BI features for their purpose of reporting. However, they require 10years of data, whereas current BI environment holds only 2 as per requirements defined by majority stakeholders.

Please advice on how this scenario should be addressed? Would it make sense to come up with different Arch with Different infrastructural set up? Wouldnt this decentralize the BI? If 10yrs worth data from source is brought into current env, it may hamper the current set up as it is not designed for this.

What should be the approach for such a requirement.

"Show me the money" should be the words right after yes we can do this. In the end, the cost will become prohibitive and the requirement will be dropped. And yes, you should redesign from the top down if your current architecture is designed to support 2 years of data.

The question I have is: What is your environment now that requires you to reconsider the architecture because you need to add more data?