This isn't really a problem with SPAs. SPAs can be fast (and if done right, can be very fast). SPAs can be bookmarked. SPAs can have full support for forward

This isn't really a problem with SPAs. SPAs can be fast (and if done right, can be very fast). SPAs can be bookmarked. SPAs can have full support for forward/backward controls. These problems aren't unique to SPAs, either. Many server-side rendered applications have the exact same problems. The problem is just that these applications are being designed poorly. Nothing else.