Web pages don't really work without in-page/dynamic javascript any longer.
On the other hand it's now cheaper than ever to just have a full-blown webkit instance in the cloud and just sync/stream the dom tree paints to the client. A bunch of products do that, I think.
Back then we had a moat because
a) Opera's Presto used so much less memory than Webkit - after having gone through so many painful memory optimization efforts, particularly with Japanese mobile browser deliveries, but also with Symbian.
b) We figured out a way of making 90% of the web javascript work be keeping "tabs" around on the server for a few minutes and then just replaying carefully selected input events and capturing the output, with some kinda clever heuristics. That combined with the low memory usage did it.
Webkit used like 10x more memory per tab/window back then, iirc. And RAM was expensive.