Chainring wear on a fixie

[silva]

I was browsing on a rare historical photos website and came across this:
https://rarehistoricalphotos.com/students-at-smith-colleg-massachusetts/

This is dated 1948, look at how far the chainring teeth are separated, it's like half density, aka every inch instead of every 1/2 inch.
Someone here recently wrote having removed every second tooth, without elaborating why.
Apparently, back then, chainrings were produced like that.

 

[Ian H]

Inch pitch chains were common back in the day (inner link was solid), hence the inch-pitch ring. You can run a half-inch chain on it no problem, but not vise versa.

 

[silva]

How does a "solid" inner link differ from nowadays inner link?
2 outer plates, 2 inner plates, 2 pens, 2 bushings over the pens, 2 rollers spinning over the bushings?
I found this:
http://www.american-vintage-bicycles.com/home/vintage-bicycle-parts/skip-tooth/
"skip tooth" chain it is named.

The inner link plates are longer than the outer so not equal gaps between rollers.
1 gap is big enough to accomodate a tooth, the other isn't.
The rollers are alike in pairs, so between 2 chainring (and then also rear cog I suppose) teeth, instead of 1 roller, 2 rollers.
On the 1950 dated pic I linked, not that detailed to be sure, but it does look like that, you see more white / background every second link.