Because I expect stricter regulations with regards to boiler emissions in the future, and this will make it increasingly more difficult for charcoal fired boilers to remain competitive because the cost of complying with stricter regulations will eventually outweigh the savings generated by using lower cost fuel (coal vs. oil or gas). This is what happened in North America over the years. Both Canada and the US have massive reserves of coal, yet most homes in both countries are heated with either centrally generated steam or oil/gas fired boilers. Of course, greener energy like solar will be used more often, but it will not become the primary source of heating energy for some time to come due to capital cost.
Also, since the cost of buying energy is going up, people will inevitably look for lower cost alternatives, such as district heating, and investors will see this as an opportunity to cash in.
Remember, most of New York City is heated by centrally generated steam, and the same goes for many other large cities. If it can be done in NY, it can be done in Krakow. It is not easy to retrofit a system to an existing city, but it can be and has been done elsewhere.
I am not very familiar with Skawina, but with will, and equally importantly, money, they could probably get their steam to where it is needed.
Technically speaking, the distance that steam can travel depends on the quality of the installation and the pipes being used. Hot water is easier to deal with, but carries lower energy content and therefore larger pipes and higher flow rates are needed, which results in more energy being used just to pump the heat carrying medium.