They already pedestrianized the original strip, North Fremont St. And even put a roof over it and covered the ceiling in LEDs and ran a zip line under it.
Vegas Blvd reeks of Tyson's Corners. Cheap real estate with zero zoning. Mega corps but huge tracks of lands and run their own roads with no coordination. If you want to pedestrianize it, then every casino along it will have to reroute whatever roads through their property to the roads behind them.