In 2 minds about this, I am part of a mixed age couple I am 63 DH is 69, he still works but next year when he retires his state pension and private pension gives him an income of about £10 over the amount a couple can get in PC so If I lost my job and the rules remained the same we wouldn't get PC anyway and would have to live on his income alone until I get my own pension in 2021- actually even if DHs was under the limit I think I would be told to cash in my private pension early anyway - but what ever the scenario we wouldn't get it, which is fine by me we would still have an income that we could live on
However I have a friend who is the same age as me, her DH was able to claim PC at the age of 60 because that was the age a woman could get her state pension, she hasn't worked for 9 years, she can work if she wanted to but has a joint claim with her DH and doesn't even have to look for work now that's wrong IMO.
However I do see the problem if the working age partner is in poor health or has caring responsibilities