It is true that everyone wants to have perfect parents, perfects relatives, friends. Unfortunately not always it is possible.
So my personal advice : MAKE YOUR LIFE. Yes, you must tell them what you want from them. Develop yourself, then it would be easy to help them. Many times advice does not help. Then it will be late for you.
I am deeply convinced your parents cannot get rid of these "bad" habits as you mentioned above. People over 40 are hardly to change even though they do not think these behaviors are proper and appropriate. It is simply because their conception, stereotype, lifestyle or conventional image have been firmly embedded in their mentality that is basically impossible to alter at all.
Accordingly, I would suggest you focus more on what you intend to do and ignore of what they are doing. Giving them some degree of freedom to try errors might be an alternative that may you happier. Parents are the people who give birth to you but they cannot totally decide your destination if you have great clear vision of your perspective.
I think liking tv series and movies is not a bad thing but, anyway, that is beyond the point. I think what you should try to do is get your parents a hobbie. I don't know how old your parents are, but I guess they are pretty old since they've already retired... but, on the other hand, if they are investing in stocks and watching series etc, it means they are still 'interested in being active in life", I guess. So here are my suggestions:
1. Get them do learn a language through a presence language course for senior citizens. Here in Brazil there are many such courses. You can maybe get them interested in a language, have them learn a little bit of it, and them get them a trip to a country where that language is spoken with the money you will have saved from your father "betting" on the stock market.
2. You could have them start a huge variety of courses: craft, writing, calligraphy, sports, etc.
3. Maybe traveling, overseas or around the country, to get them to live different things.
This are my suggestions, but I know it is hard. My grandparents are around 80 years old and they don't want to do anything we tell them to do. It has a lot to with the generation gap you mentioned, sure, because in my case they were raised in the rural early 20th century Brazil, so they are very different from post-modernization generations like my parent's. I think this may be a problem, if your parents have this pre-modern mindset of people who can only work and not enjoy their lives otherwise (they dies working, and didn't retire). Then you might consider getting them a job or some other kind of occupation.
Jack, imagine you have a child, who lectures you about your life. Your child, who doesn't have your life experiences, constantly moaning and making you look bad on italki. The child you raised, who now has a good life because of your hard work. What would you think?
You need to stop this strategy because it will not work even though you have good intentions.
All you can do is chat with them, go out with them, bring the grandchildren to them and assist when they ask. If you have siblings, let them be a part of it.
You are a child to them and will always be their child.