…Russian shuttles could be completed…

I doubt the Buran technology can be used now (since it’s too old) nor parts can be exchanged with the Shuttle

…not too sure about the Orion anyway…

probably the Orion’s timeline will be different than planned, but I’m sure it will born someday

…vehicle as versatile as the shuttle is also required…

yes, a new, safer and cheaper Shuttle may be useful, but NASA has no money to build (both) the Orion and a new Shuttle while privates lack of (both) funds and experience