It's quite possible that if you have large pile of money you can still get it (https://www.itasoftware.com/ has list of existing customers, and Sales button at bottom - I have no reason to think that customer list isn't still valid.)
And at a very minimum Google is using this for Google Flights, that's what they bought ITA for.
There's other companies that will sell you the data, if you have a large pile of money (Sabre, Amadeus, etc.).
So it's problematic insofar as they're making it much harder for random small companies and hobbyists to get it. On the other hand, pre-acquisition this public API didn't exist. So it's not clear Google's acquisition of ITA made things worse in any way.
(Disclaimer: used to work for ITA. Have no inside knowledge of how things work now.)
There's other companies that will sell you the data, if you have a large pile of money (Sabre, Amadeus, etc.).
So it's problematic insofar as they're making it much harder for random small companies and hobbyists to get it. On the other hand, pre-acquisition this public API didn't exist. So it's not clear Google's acquisition of ITA made things worse in any way.
(Disclaimer: used to work for ITA. Have no inside knowledge of how things work now.)