I suspect custom renderers will stick around because of the additional control over rasterization you get and the ability to rasterize from the same internal bu

I suspect custom renderers will stick around because of the additional control over rasterization you get and the ability to rasterize from the same internal buffers that you use for editing and syntax highlighting. If a file contains tens of thousands of lines (not uncommon these days) the cost of duplicating all of that to a complex HTML+CSS tree is not insignificant, even if contain reduces the cost of it. Even now it's not hard to get the github code view of a large file to lag a bit in Firefox when scrolling it because of how much layout and rasterization has to happen (in part due to the way they aggressively syntax highlight the text and split lines into elements to include line numbers) Another example - if you haven't done it recently, try opening a 10mb+ text file in chrome or firefox. The experience is still somewhat bad.