I agree with you that pensions have changed a lot, and there are better choices for people now. I'm in no way recommending that they should be ignored, it's just that they are not always great on their own, and if you can afford to have a mix of options then that is better, just my view though. As you say, it's too complex for quick posts, and really any advice needs tailoring for people's individual circumstances. Doing nothing really is a poor idea though.
If you don't have a pension or lots if money you will either never able to retire or you will have a poor retirement.
When you are younger you want minimum medium risk on your investments. I split mine 70% medium and 30% medium/high. I am now 40% medium and the rest lower. My high risk part did well. But it is a gamble you can only take when younger. Once it is gone it is gone.
The present state pension is a good base to work off. If you are entitled to a full one and there is two of you that is about 16k a year. If you only manage to secure a way of getting 8k a year you will have 2k a month to live off. A drawdown pot of only £160k will make it happen for at least 20 years if done wisely. Share the tax burden and you won't pay tax. If you don't take the tax free 25% you won't pay tax on 25% of what you take out. By then you will be old and sitting in the corner dribbling all over yourself.
The money you put in while in your 20's will be invested for about 40 years. It will be worth many multiples of what you put in. And remember that every £100 You put in only cost you £80. Then you have employer contributions.
For those who can afford it the choice is lifestyle or finish work years early. We only have two cars on the road now. The family car which is a 2008 and a fun car that is 2003. Both very reliable. Not having new cars pays for my pension. We don't do expensive holidays where you just sit next to a pool or on the beach. This saving stays in my bank account. It has been hard at times but when I am 55 I could afford to retire. But just staying at work until 59 would make a massive difference. Over 4k a year plus over 30k more minimum in my drawdown pot.
It can be a complex subject. But once you get the basics the rest becomes easy. And never forget the state pension is a good start. Top priority is owning somewhere to live when you retire. It doesn't even have to be a house.