Why do mecha anime tend to be original works? So this may seem like a weird question, but bear with me.

Loads and loads of anime are based on manga, and it's a fact that has become well-known in the anime community. However, the mecha genre seems to be a tad different.

I've seen a decent amount of mecha anime in the past. However, one trend that sticks out to me is that a lot of mecha anime are original works, and not based on manga, or light novels.

Here are some examples that I was able to gather by going through the mecha genres on MyAnimeList:


Gundam franchise- is technically a multimedia franchise, but started as a TV anime
Code Geass - another huge mecha franchise
Macross franchise - huge and old mecha franchise
Neon Genesis Evangelion 
Tengen Toppa Gurren Lagann 
Darling in the FranXX
Eureka Seven
Aldnoah.Zero
Suisei no Gargantia
Kakumeiki Valvrave
Cross Ange
Hoshi no Koe
Isekai no Seikishi Monogatari
Tenkuu no Escaflowne
Star Driver
Kuromukuro
Aquarion series
Heroic Age - this one's kinda iffy since the giant beings they transform into are organic (kinda like Attack on Titan), but MAL categorizes it as mecha


All of these are original anime, or started as original anime. However, when you look through other genres on MAL, there aren't a lot other genres with this many original works.

So why do mecha anime tend to be original works, more so than other genres? Why aren't there as many mecha manga or light novels?
Well, Gundam in particular is designed to sell the Gundam model kits. Unlike American TV where ratings and selling advertising is the focus, anime generally makes money from selling Blu-rays or toys (or the original manga/light novel). So Gundam anime exists solely so they can push new model kits.