Like Jaylucy I live in the regions, so I don't have a travel pass, and have relied on public transport all my life.
I think it should be free for over 60s, regardless of income, as the more people who use public transport the more likely it is to survive cuts, and as has been said, reducing the number of cars on the road can only be a good thing. If buses are running anyway, it's not as though letting over 60s on free is going to cost much, but it could make a lot of difference to people's lives.
I was lucky enough to be able to leave work before state pension age, but that doesn't mean I am well off - in fact I am living off savings, and will have to do so for over 6 years. I had budgeted for living expenses, but hadn't really taken account of the things that used to be free or concessionary for over 60s that we now have to wait for until we are 66 or 67. A bus pass would make all the difference, as a ticket to my nearest town costs £8, and I have to go there at least twice a week.
I also think that there should be a nationwide approach to concessionary travel. We all pay the same taxes, so it seems unfair that there is a postcode lottery when it comes to travel passes.
Finally, I also think that discussions like these (not particularly on here, but in general) are a way of softening people up for a means-tested pension benefit, which would, IMO, be massively unjust, as so many people paid into an occupational or private pension believing that it would top up their state pension.