With all due respect, if someone does a crime and tries to escape by air, I think they will just get on the first flights that they can, days if not months before any police force would confirm a criminal's identity, update listings and arrange for people not to be able to fly off. If someone does something really bad, his/her identity is confirmed, and it is suspected that the person will try to flee, there is still absolutely nothing preventing police forces from creating an alert, sending it to police forces in border areas, stations, ports, and airports, diffuse the person's photos and characteristics and hope for an arrest. Indeed, I can confirm that French airports are still full of police personnel and I suspect that many criminals would choose some other less conspicuous escape route. European police forces do not rely on airlines to do their jobs, gate agents are undoubtedly not trained to spot fake ids which the criminals you mention would undoubtedly use in recent years to travel on fake identity, and I genuinely think that the change makes absolutely no difference in that particular respect.

You are absolutely right that there are many occasions in life when one is asked to show id, and many others when one has to go through security. Everything is possible in theory. In some countries you have to pass security to enter bus or train stations or even shopping malls, which undoubtedly lowers the likeliness of terrorist attacks in these places, in others, policemen can ask random passer by's on the street to show their id which undoubtedly results in some 'wanted' people being spotted and arrested or illegal immigrants being found, in others you also need to show id when you leave individual cities which presumably prevent wanted people from disappearing and becoming much harder to find.

There is no limit to what can be proposed in the name of security, but ultimately, public forces need to arbitrate based on a number of criteria including efficiency, marginal benefits of each additional measure, the right of people to live as normal and undisrupted a life as possible, cost, etc. My personal perception is that removing this particular control is an improvement and very much goes in the right direction. I am yet to hear many people who think that US airports are dangerously insecure yet both security and id checks for domestic flights are much laxer than what we have in Europe.