I agree with the first part, disagree with the second.
There are a ton of seasoned reefers who don't have the capability to both internalize those lessons, and then teach them - so you get threads where a newbie is having issues with corals not doing well/algae/whatever, and has 1ppm phosphate and 150 ppm nitrate, and you've got old hands chiming in with "My 400g runs at 1ppm phosphate - so its clearly not that".Or "I run my tank at 16 dkh, so your alk definitely isn't the problem". Things that work in established tanks often lead to disaster in new tanks - and people with established tanks often give very well meaning advice without understanding that.
For instance - you have old hands saying stuff like "Oh, SPS won't survive in a tank less than a year old" when the truth is really that SPS do just fine in newer tanks as long as you cater to their needs - and the old hand is just assuming that their experience as a newbie is a reef truism, and not a result of them not understanding that new tanks have to be handled completely differently than old tanks, and the advice they were given - that now works on their established tank - was awful advice for a new tank.
@CollectOyster04 s tank is a good example of the transition from new tank to mature tank, and that swapover from net waste producer to net consumer - the rules of reefing completely change when the tank hits that point - and pretty much all the management of the tank changes - and its a tough part for a lot of people because so much of the advice that has worked for them no longer does - and everything they've learned - all those newbie lessons - aren't relevant.
Some people go through that paradigm shift and understand what happened - some go through it - and don't.