Try being over 60 & gettind cred. "How could you possibly understand bleeding edge tech and emerging trends?" Well...I've lived there for four decades, you?
Which knowledge is deeper? That of the user, or that of the builder?
I've designed some of the bloody devices, for God's sake! I just don't want any because I have no use for them (either because I get the same function another way I do prefer or because I consider the function pointless or harmful). It doesn't mean I don't understand them better than the average candy crusher.
1. (positive) Big picture wisdom increases. You learn when to call in help, when to use a library instead of rolling it yourself, when to stop hacking, retreat, document, how long to architect, etc. I get a little frustrated with younger people who e.g. over-optimize some aspect of a system before making the whole thing work adequately. I am waaaaaaay more organized and consistent than the young person who hasn't inherited enough code or faced the spectre of their own code when they forgot how it works.
2. (negative) I often forget how easy some formerly difficult tasks have become. Just take a library like three.js.... or building a compiler from source or using a library instead of writing an XML parser or SDL and so on. To stay on top, I often have to check in with others to see what surprising tools "young people" :) have made. This is critical because it affects estimates of time and resources needed to meet a goal.
So it's excellent to be around for a long time, IMO, as long as you are good at forgetting/unlearning some obsolete ways of doing things.
It doesn't add much value to the conversation and whether some tech is really a rehash or not rarely matters. It also makes you sound cynical.
"I've seen people try that 5, 10, 15, 20, and 25 years ago. Nobody made it work." Is rarely something that does not matter, and people that can't answer the implicit "why would you succeed?" question usually doesn't.
There's plenty of amazing innovation happening all the time, so I don't want to come across as a luddite or whatever, but hype does happen, and as you get older, you witness more of it and become more skeptical of it. You see the fads come and go--the faster they come, the faster they go--and the survivor bias. The problem is that it's there, and it feels sometimes like you face the choice of correctly pointing that out, or being labeled a cynic.
Good, because my cynicism was hard-won, pity should it go to waste.
Whether or not a piece of tech is a rehash does matter, because last time we decided RDBMSs are old, in with the new open schema whatever, I learned where the sharp edges were at. There has been no magic tech in the mean time that makes MongoDB less likely to cut you up in horrible ways. As just one example.
It's not that you don't understand the bleeding edge tech, it's that you've seen this pattern play out so many times it's hard to look at it as more than just another programming tool.