Given who one of Brocade/Ruckus/Commscope's customers is for the 7450 and how widely they've deployed them, it is very unlikely they will EOL the 7450 any time soon. The organization I work for has literally thousands of them deployed - I believe last count I saw was over 5,000 hostnames, with a fair chunk of them being stacks (so more than that for total chassis).I know the 7450 could go EOL at any time, but it still gets me 1+ year ahead of the 6610 on bug/security fixes.
That should generally apply to any 7xxx Brocade at this point though.