My suspicion is that customers are bugging them to support large files in emFile and they don't want to pay the license fee for exFAT. I think they even can't do that with their current licensing model, which is one-time per product (not item) or product-family payment.
EDIT: I tried to find out if Microsoft's exFAT is licensed per product or per unit and I found that it used to be a 300000 USD flat fee in 2009 but seems to be free since 2019. So my theory from above has no basis and I wonder why Segger does not simply implement exFAT?
Source:
https://www.microsoft.com/en-us/legal/intellectualproperty/t...
https://www.paragon-software.com/exfat-license/
https://en.wikipedia.org/wiki/ExFAT#Legal_status
You maybe of the hook if you use Linux >= 5.7. And it seem that you are of the hook if you are a member of the Open Invention Network (OIN).
But SEGGER's embOS is not based on Linux and their costumers a OEMs themselves. So their costumers would need to be OIN members or pay royalties to MS.