[wmil]

They could if they were building it now. IE got pushState support in IE 10 in 2012.

The hash state has been there since Instant Search was launched in 2010.

[lloeki]

Graceful degradation/progressive enhancement is a thing, though.

[bpicolo]

The amount of money Google makes supporting older browsers is most likely measured in billions.

Not to mention, why fix something that isn't broken? There are cases for it, but it's roughly the same tech that it was 4 years ago. What would they gain by spending developer time on it?

[iurisilvio]

Perfect. They definitely don't need optimization for search engines, which is probably the most important reason to a clean URL.

[adamdonahue]

Exactly. You are someone who gets it.

[heisenbit]

I suspect they spend a ton of developer time. It is their #1 source of income. What they won't do is releasing it unless it is 99.9% certain that it yields an improvement.

[untog]

Yes, but in this case the benefits of the enhancement are small enough that Google may have decided that consistent behaviour was more desirable.

[paulddraper]

Consistent and long-lasting support is a thing too.

Rare on today's web, but still a thing.