Grandparents parenting

Harleena Singh lists the following reasons why grandparents are playing a bigger parenting role with their grandchildren these days compared to the past:

• Compensating for the effect of death or disability of a parent;
• Helping as parents go through divorce, separation, etc;
• Reduce the children's contact with their parents because parents have drug abuse or mental disability type of problems;
• Catering for a home-like experience to help shape the children's cultural identity;
• Support because one or both parents are in prison;
• Help children out in cases of parental abuse;
• Help children abandoned by their parents, or when parents are away in military service;
• Help out their children in the case of teenage pregnancy;

I think all these are valid reasons, and I appreciate grandparents' help.  However, I also see that in a lot of these situations, it is because something went wrong in the lives of the parents, that the grandparents step in to cater for the children.

Is this right?  Should parents be more responsible?  Should the responsibility be undertaken by grandparents, do you think?

I see that sometimes, it is because both parents are employed full-time, or working overseas, that parents take on the parenting role.  It might be greed for more money that this happens, although Harleena also mentions military service as one of the reasons.  I see also that as the cost of living in the cities increase, that it might not be financial greed, but purely necessity driving this trend.

What do you think?  Is this a good trend, or a not-so-good one?  Is the economic reason a valid one?  If this trend is not good, then what would be a better solution?