Russia doesn't spend money to modernize its own industry, WHY, in all that is holy, would they spend money on Ukraine's? If I were to guess:
- Because it's cheaper there:
- The labor is cheaper, and plentiful, and highly educated.
- There are many railways and roads, as well as water transport (very cheap.) This includes access to Black Sea and, consequently, export paths through Bosphorus.
- There are existing facilities, so that the investments can be smaller. It's much cheaper to renovate an existing steel mill in Donbass rather than to build a new one somewhere in Siberia, in the middle of nowhere.
- Because the pollution stays in Ukraine. Immoral, but actively used by every "green" European country like Sweden (they exported most of their dirty energy production to Poland.)
- It benefits Russia because it creates economic links to Ukraine that are not as easy to break (compared to Ukrainian President today deciding something and tomorrow undeciding that, as a true master of his word.)
- Some technologies stayed in Ukraine, like production of specific sorts of steel and other alloys. Some Russian designs call for those alloys. Redoing the design costs more than just getting the material that works.
- It benefits Ukraine because it gets richer and happier. You want happy neighbors. A politically unstable Ukraine is dangerous. They do have nuclear power stations, and an "accident" on one of them will be heard (and measured) all around the world.
- Many Russians have relatives in Ukraine (and vice versa, of course.)
- Politically, friendly Ukraine is a barrier against NATO.
This is not to say that development within Russia is out of question... but Ukrainian resources are already there, right across the border - they are just poorly managed (which is obvious.)
A similar set of facts is the reason why your computer is built in Taiwan from parts made in Malaysia. It's not a conspiracy of Dell and IBM and HP - it's caused by natural reasons that apply to everyone. This is why the USA buys steel from China instead of upgrading domestic steel mills (say, in Pittsburgh.) [Today you'd die from old age before you negotiate all the red tape paperwork with EPA.]
Your points make too much sense, unfortunately, this is not how FSU Russia and Ukraine operate. There is no economic vision, neither country is making investments, and if there are investments, a large portion is wasted through corruption. In all, Russia is just as inept as Ukraine (I mean there is less than a week left till the Olympics and they're still building hotels in Sochi)
It benefits Russia because it creates economic links to Ukraine that are not as easy to break (compared to Ukrainian President today deciding something and tomorrow undeciding that, as a true master of his word.)
Conclusion for Ukraine should be the exact opposite. If Russia throws a tantrum and closes border when Ukraine makes a political decision, it is not a reliable trading partner, and Ukraine should not walk, but run the other way