Let's be honest: In terms of sports injury issues, baseball pitchers getting hit by line drives isn't exactly in the public discourse like NFL players and concussions. Nor should it be; according to ESPN research, 12 pitchers have been hit in the head by line drives in the past six months, a far cry from the damage football inflicts on untold brains.
That doesn't mean it isn't an issue worth addressing, which is why the new protective cap that MLB approved and pitchers will have the option of wearing is sort of a no-harm, no-foul situation. Pitchers can try the new cap in spring training; if they feel comfortable with the lining, you'll see some continue wearing it during the regular season.
You probably won't see many pitchers wearing one this season, however. There will be initial reluctance. Look at the history of batting helmets, which became standard in the 1950s but not required until 1970, and even then veteran players were given the option. The last player to bat without a helmet was Bob Montgomery in 1979. Helmets with ear flaps became popular in the mid-'60s, but weren't mandatory until 1983. Again, veteran players were grandfathered in; Tim Raines was the last player to bat without an ear flap, in 2002.
So I would predict it will take years for the protective cap for pitchers to catch on, unless baseball makes it mandatory at some point. I suspect the bigger impact will come in youth baseball, where you can see this type of cap becoming mandatory.
There's nothing wrong with that, of course; safety is important. At the same time, sports are not without risk. We can't expect a sport where a hard leather sphere is thrown or hit with great velocity to be a risk-free environment. Injuries will happen. If you're worried about getting hurt, go play checkers.