If you have a good reason for complex pages your solution is only viable once the share of old browsers has dropped below, say, 5% to 10%, depending on your nic

If you have a good reason for complex pages your solution is only viable once the share of old browsers has dropped below, say, 5% to 10%, depending on your niche. What's actually going to happen is that most people will layer JavaScript frameworks on top of HTML and then we're going to complain about the huge performance and memory overhead of JavaScript heavy websites.