Actually they were made for other languages given the original goal of Common Language Runtime, as published on the 2001 release note.

https://news.microsoft.com/2001/10/22/massive-industry-and-d...

Anyone with the pre-release MSDN .NET SDK that was initially made available to MSFT Partners, with alpha documentation written in red, has a folder with tons of functional languages that could take advantage of tail calls.

F# only came later into the picture, even considering its OCaml for .NET origin.