The amount of concurrent webgl canvases on a page is limited by browsers. I believe it's somewhere between 8-20 depending on the browser.

Hopefully webgpu would lift that limit?

I guess, the trick is to keep everything inside on stage. But why would I need more than 8 stages?

I have allmost unlimited pixi containers.

(And HTML and sometimes a ordinary canvas on top of my pixi canvas)

Those are just sprites rendered onto the same canvas, not multiple canvases.

The idea with pixi is, that you have one HTML canvas. But every sprite can also be a graphics object/canvas.

Which makes it ill-suited when you need multiple canvases. Pixijs is amazing, and I mix Pixi, Fabric and regular canvases in my application.

I still would be interested in a use case for more stages. My stagecanvas is the background of the html document. And there I have many layers with different zoomlevels etc

Everything pixi goes there. And can appear exactly on the screen when and where I want. If I ever would have a use case of a second pixi layer above my html elements layer, I can do that. So I am really curious, what else one could need?