My thoughts are that you have to manage risk just like you would in a business. Not all risks need immediate and rash decisions.
I think that yes, old players today may be at risk due to balls being very heavy especially from rest. Todays players not so much. Footballs we can all buy in the shops are incredibly light and official matchballs used at top levels are even lighter. I don't think its possible to bad heading in football - would completely change the game.
There are many other sports where the risk of head injuries being caused by contact is much higher. Boxing especially in the heavier weights, ice hockey to name a few. I also agree with a previous point that further research is needed to see if there is any hereditary link that might make a player much more likely to get to unfortunate disease.
However, if a direct link is found it would be hard to not stop heading. Dementia is one of the worst things you can see someone go through.