"They didn't need to go to any further trouble just to keep TT alive on Win 10 for a year, for what would be a very small % of their user base" -- Check your facts. Only ~50% of windows users are on Win11 and around 40% are on Win10. So that is a significant number of their userbase. What they are actually doing is pushing users to move to TurboTax online (they tell you that right in their messaging), but many of us don't want Intuit having our information on their servers waiting to be hacked and refuse.
"TT can build in their own security if they chose to" -- I think there is a misconception here. Sure, Win11 uses TPM to secure the OS. But TPM has been used for decades on Servers (and some PCs) to secure data. Intuit probably made use of the required TPM hardware to help secure your data. Not an MS feature, a hardware feature provided by the motherboard. Intuit still builds their own security separately from the OS. Intuit is likely taking advantage of TPM , now that 100% of their users will have TPM hardware on their motherboards. What will be interest is if those that install Win11 with the workaround of using Rufus, which has an option to remove the TPM 2.0 requirement from the installation media, will still work. TuboTax may still look for the TTM hardware to secure the data files and if not present, refuse to install.
What is TPM ? Think of it as a hardware key. Without TPM , your data may be protected by a password. But passwords can be hacked. With TPM your file is not only password protected, but encrypted by a hardware key that is present on your motherboard. If someone steals your data files, they will not be able to decrypt the files and read all your data.
