I read many posts about the Intel RST requiring .NET 4.5 here on TenForums and it bugged me that this was an issue. The 4.6 CLR is the same as 4.5. What Greig Mitchell sleuthed out was that it wasn't .NET, but a reconciliation issue between the OS and .NET for the installer.
Intel punted on it - shame on them.

One of the great mysteries solved ... hopefully.

Install Intel Rapid Storage Technology Driver on Windows 10 | Greig Mitchells Blog

What you need:
Intel Rapid Storage Technology Driver (Duh!) Link
7-Zip 9.20 or 9.38 Beta Link

1. Extract the SetupRST.exe file with 7-Zip
2. Right click on the MSI installer for your OS type and select “Properties”
3. Under the Compatibility tab select “Run this program in compatibility mode for previous version of Windows”

That’s it! All you need to do now is install from the MSI file and it should be successful
OS type in the context above is 32 bit (x86) or 64 bit (amd64)

If this works for anyone having trouble installing Intel RST, please drop Greig Mitchell a little love note.