In the current game, it always spawn a large amount of a few types of industries (especially in pak128.Britain.Ext), which makes the freight transport network repetitive. I hope there is an option to make each of the industries only spawn at most once (or other fixed number) on one map. This option is present for a long time in OpenTTD, by setting the number of industries to 'minimal'.
I am currently playing with passenger-only maps, because I found freight transport extremely boring for me, especially when it fits into my playing style to connect all industries and cities.
Standard will spawn a chain for a single good time. Because unlike OpenTTD, you cannot start transporting unless there is a consumer for the goods that are produced.
In case of the supermarket and other consumers with multiple goods, separate chains spawn one after the other.
I later game states it depends on the availability of goods on how many factories will spawn. If there is enough produced, then only a consumer will spawn.
But in extended, an unreasonable amount of industries can spawn. Example here: https://forum.simutrans.com/index.php/topic,22150.new.html#new