I am not the backer.
Streaming starts a little earlier. This is exactly to filter out some presale projects, that just sell overpriced rebranded products that already available on other markets, sometimes with better battery, better enclosure, better app, etc. Presale projects still can stream, everything is fair. If project owner do not want to stream, then edit and upload afterwards, backers probably will be less interested in such projects.
When someone visits project page, there would be live feed and recorded content. Similar to YouTube, it is possible to highlight most viewed moments and filter out large chunks with mo movement of on the screen. And anyone can comment, ask questions. It must be interactive.
Who would agree to pay some strangers after watching a short video and few pages of advertisement text? Surprisingly, a lot of people do pay, and that's how it works now. Probably, because crowdfunding platforms still have some
reputationn left, and some good projects pop-up from time to time. What I propose is to replace early 2000s style monthly updates and short videos with live streaming. Just an upgrade. Old way may be still there for those who do not want to stream. It's a platform, let backers and project owners decide.