Wow, here we go again. In my experience from Jeubert, to plenums, to fine DSB, to bare bottoms. Warning: all anecdotal although I have been in the hobby for over 25years and I have science degrees

Not that longevity matters, you could be doing something wrong for 25 years, LOL.
Plenums and Jeubert and Deep Sand Beds: Eventually do reach saturation of nutrients (in the sandbed), when, is only a matter of time. I had a 29gal plenum for many many years, until I could no longer keep up with the phosphates.
I ran it skimmersless for the first year and did great. Second year added a skimmer and still did great. ABout 7 years down the line I could not stop hair algea. But back then I was not as good at lowering Phosphates. Since ULNS like Carbon Dosing and Lanthanum Chloride additives, I think I could have even better luck. The water column always measured really low nutrients.
My deep sand Bed tank also thrived, but I only had it set up for less than 5 years and when I took it out, you could DEFINATELY smell the nutrients. I did not reuse the sand. The water column always read less than 20ppm nitrates and less than 0.005ppms of phosphates.
Barebottom, like everyone else before me said. It allows for more flow, however, its NOT really easier to keep clean in my opinion because you have to use MASSIVE flow to keep the barebottom from detritus build up and that = maitainance of multiple pumps in hard to reach areas but the worst part is VACUMING the spots of detritus, especially behind the rocks. You either vacuum the spot or add flow by adding a pump or have your nitrates rise.
Bare bottoms Definitely take A LOT less carbon dosing and Lanthanum to decrease N and P (a lot less so you can bleach and starve your tank VERY easily. I feel I have to be VERY careful dosing carbon and Alk with a barebottom tank hence my conclusion a sandbed buffers alkalinity and nutrients.
Now, which do I prefer and why? A Shallow sandbed that I can replace the sand when I vacuum.
If the tank is gonna be set up for less than 10years, Deep Sand Bed. Because it does help buffer alkalinity AND nutrients. And by the time its ten years you will be replacing the sandbed, anyhow. If you've used carbon dosing or Lanthanum, you can strip the phospahtes really quick from the water ; Ive noticed with a Deep Sand Bed, its harder to overdose your carbon. I feel when the water column gets too stipped of phosphates and nitrates, the deep sand bed realeases some due to dilution from the sandbed to the water column.
So the length of time you're going to keep the tank makes a HUGE difference on whether to use a deep sand bed or not. Because of the nutrient sinking and cycling. I hope this helps a little bit.