Lack of skilled IT workforce, but they do not raise wages In my country, Portugal, many IT companies are always complaining in media regarding the lack of skilled IT workforce, but they do not raise wages. We have statistical data from the government that proves what I am saying.


Companies are paying less in 2016 than in 2011 for IT workforce (-10.2%). GEP/MTSSS
From 2014 to 2017 there is a decrease of IT workforce from 110.900 to 104.300 employees. Eurostat - Employed ICT specialists


So, the facts:


Companies are paying lower salaries
The number of it specialists also decrease (probably emigration).


If there is a shortage of workers, as the companies saying, why the law of supply and demand does not apply in this specific labor market?
The factual observations you've listed fit neatly with the law of supply.  You've seen that wages (price) have fallen, and during the same period, supply has gone down.

The fact that companies publicly complain that there aren't lots of cheap, highly skilled workers available is not the same as companies being willing to convert that into effective demand by raising wages.

One common reason companies moan about things publicly, for instance, is that they want the government to intervene to help them.  In this case, perhaps they want government to provide more subsidised IT training, or permit more immigration in the sector, either of which could lower wages further or prevent them from rising.