TOPIC:

you mention the word "advantage" several times. That doesn't exist!!
If you start with a cargo that doesn't give secondary/tertiary production. it's already well paid (example: Coal). This way, company doing Coal is already in "advantage" compared with who starts with livestock or rubber (only examples because pays like crap). So there's a balance, right?
Other example: all companies start delivering different factories, fully respecting rule #3, meaning that all companies are in "advantage". Seems fair to me too!

Among the years many players tried many ways and excuses to "steal" other people secondary/tertiary products. Maybe your intention is genuine but past examples keep bringing that to my mind

There's much more examples where a simple change on rule #3 could lead to abuses, and time (years) led us to the current rule, since balance more what each company makes/builds ingame.

ST2, would two companies still be prosecuted for breaking rule #3 even if the "First come, first served" player asked the other player to take some raw materials to the factory??

EDIT: I suspect they would

Ok, and what about people and post in cities? If you build city, like you transport there post, goods, passangers, use some actions to grow up, then some of the other player came and can steal your passangers... Thats ok? For me its same like the "goods" rule... You built it first, so why others can use it?

That isn't possible, NO other companies can build things in your town meaning they CAN'T steal anything. In a CITY however, anyone can take passengers/mail too and from the CITY.

Yeah but just only on servers where you play on city population, but thats not what i am talking about... right?

What are you talking about then?

EDIT: I don't thing there is any need to build a big city on any other type of game other than CB (CityBuilder)