We have a chain of command in our government for when people die. First the President, then the Vice President, then the Speaker of the House, then the Secretaries in a predefined order, and so forth. Plus, the Secret Service (which protects the president) includes considerations for, say, Nuclear Bombing of the capitol and who would take over leadership if such a disaster should happen.
If the rioters had succeeded in murdering every single person in the capital building, there would have been a protocol in place with the leader already determined. The only way this would have been successful is if the rioters killed every single elected official and secretary in the building, followed by having the support of the Army. They were absolutely nowhere near that.
The president (and president-elect) weren't anywhere near the building and their safety was not at issue.
There is no federal procedure or "chain of command" for replacing individual Representatives and Senators -- that goes back to the states they represent, with either elections or appointments.
Many people in the populace would have supported it, look at how many now even today deny that it was a riot aimed at disrupting the peaceful transition of power of the government.
If they didn't do a good enough job at it, it doesn't mean it didn't happen.
Around 75% of republicans believe Trump won the 2020 election, and that number has been substantiated by multiple polls at this point. I'd like to say that the coup attempt didn't have the support of the populace, but frankly I'm not sure.
If the rioters had succeeded in murdering every single person in the capital building, there would have been a protocol in place with the leader already determined. The only way this would have been successful is if the rioters killed every single elected official and secretary in the building, followed by having the support of the Army. They were absolutely nowhere near that.