I helped with the Eve language, which was a VC funded attempt down this path (https://witheve.com). This was cut short when the money ran out, so it wasn’t a full attempt.
After that project ended I started working on my own attempt called Mech which specifically handles the time-travel and what-if features you mentioned (https://GitHub.com/mech-lang/mech you can play with an early alpha version here: http://docs.mech-lang.org/#/examples/bouncing-balls.mec). I’ve made sure money running out won’t kill this project, so hopefully it’s a fuller attempt.
Someone else posted a link to futureofcoding.org, which is a community that works on these types of projects. You can find a lot more there.
After that project ended I started working on my own attempt called Mech which specifically handles the time-travel and what-if features you mentioned (https://GitHub.com/mech-lang/mech you can play with an early alpha version here: http://docs.mech-lang.org/#/examples/bouncing-balls.mec). I’ve made sure money running out won’t kill this project, so hopefully it’s a fuller attempt.
Someone else posted a link to futureofcoding.org, which is a community that works on these types of projects. You can find a lot more there.