If a shipping line liquidates itself (no ships, no money), then it should be removed from the list. Combined with the rule that a new line can only be created if every existing line has ships, this would limit the number of shipping companies.
I agree.
I believe Steve cannot see yet the effects long term on both Subsidize button removed and also the dividend glitch (imported from VB6 version) therefore he is still simply not able to tweak this part yet. I am sure that as soon as he'll go for a stable 100/200 year game test run he will also change a few other things such as maintenance that is looking very expensive at the moment. It is same as the wealth revamp, which was good and then he needed to change again based on the few first tests; he may change that again if he sees that it's not working with larger empires.
It is part of the development and the balance, so I will be prudent before pointing out something radical.
From the 5.12 version which was for long the standard to the 6.0 there were many changes in VB6 which were made after years of intensive gameplay. Based on the fact that fundamentally Aurora C# is the same game but with few more features we can assume that Steve's work is not only influenced by the balance that these new features comport but also by the experiences he had during the whole Aurora development. Especially when it comes to feature interactions.
In fact, on final note sometimes it is not only the single feature (ie shipping lines) but how that feature is linked to all the others. In this case, we have a small tree that could be expanded exponentially but if kept at bare would still be:
Shipping Lines -- Civilian Ship Spawn -- Civilian Ship Design
The above still not touching the Logistic or the Wealth.
I think the key and probably what Steve is also trying to keep under control is the DWARF FORTRESS CHICKENS CPU KILLER EFFECT. If Aurora C# may or may not have the issue with multiple NPCs and Civilian Companies (we don't know that yet) this is not meaning that we could just overkill CPUs (Aurora runs single threaded) with millions of single processes.
Again balance.