I am only counting the interfaces that add up to total SLOP! most of the other engines you have shown have a lot of gears but not a lot of driven interfaces from crank to each cam. The bloody antique Cosworth V-8 needed an external valve-train damper to keep the teeth from breaking off the goofy gears.
As I have clearly pointed out and you have confirmed; the wacky, OSG, L-engine, gear-drive is a workaround for form over function.
There are good reasons for the gear drive over other possible designs. OIL is key, and easy compact design so that it works with most stock component placements.
1. A belt cannot run in the oil environment of the front cover. It is a harder workaround to "DRY OUT" the front cover for a synthetic, organic belt drive, or to move the drive further forward, outside the front cover.
2. A twin-cam, 2 stage, chain drive requires multiple tensioners usually driven by oil pressure. The hardware and plumbing to tension a wet, twin-cam, chain drive would be a lot bulkier and more external than allowable due to the target market demands.
3. The gear drive is compact, fits within the footprint of the original design, and is a wacky, goofy, trouble-prone, compromise at best.