The problem is we tend to believe values and beliefs are everlasting. Fact is they are not, as time passes so do values, beliefs, ethics, etc.
This is visible in all of our lives. Go have a conversation about the simple things in life with your Grandfather or even Great Grandfather. C'mon there is a complete generational gap that embodies different core values about life, marraige, money, and w/e other example you can think of.
Furthermore the world is vastly different now then it was 30 years ago when instant gratification wasnt a topic of controversy. Technology has made the whole world available at the click of a mouse.
Personally I dont see the problem with instant gratification, thats the world we live in. What I worry about is the absolute breakdown of Family specifically Parenting. Parents are no longer involved and instead of working with their kids they shove things in the kids face to shut them up. Quite a coincidence ehh? The important things parents should be teaching their kids is absent nowdays, parents should be helping build a solid foundation and giving them the tools to make sound decisions and for the most part they dont. They should embrace the very thing they are praying their kids would have, CONTROL they have none.