Comment by ben_w

> Labour costs are becoming a bigger proportion so some installations plop panels on the ground than slant them to south (in northern hemisphere).

Even more than that: I was recently at GITEX Europe, and one of the startups* was pitching "they're so cheap, we should lay them flat for cheaper installation and maintenance".

* Their name was something like "slant solar" or "tilt solar", as they had initially thought of doing exactly what you say, but I can't exactly recall the name.