How do we overcome being nostalgic for brands?

See a nostalgic toy in the stores. Walk away

'wow a toy with an oversized head that looks vaguely like that person from that movie I use to love! Cool' then walk on. 

The more you walk away from these things the less you'll care for them. Thoughts inform actions, but actions also inform thoughts. 

'Did you see the new spiderman it's ssooo... Good.. It has all three spiderman in it. Greatest film eeevvaaw ' really? was it though? There was no character development. Story was rubbish and a mcguffin solved the day. Useless.

And if you look at most things that are nostalgia you'll see that once you look past that, they too, are useless. (star wars). 

Pause and ask yourself really? Was it really that good? Once you see things as they really are nostalgia will be a lot less effective on you.