Ask HN: Server-side web apps – is the database still a bottleneck?

I've read many times in comments here on Hacker News that the speed of your database or disk access is the biggest bottleneck for your server-side web app. Therefore, the speed of your server-side programming language is not important (or less important).

Does this still hold true? Given that SSDs are now commonly used by many hosting providers - is database/disk access still a bottleneck for server-side web apps?