What is a well known 'public secret' in the industry you work in that the majority of outsiders are unaware of?

That replacement infrastructure being installed in your area was PE stamped decades ago. It is quite possible he/she who did it has died at this point. All the mistakes they made are still in there and getting replicated with each upgrade. If anyone tries to fix anything it will be an uphill battle. Parts are specified that don't exist so without eBay nothing would get shipped.

The person managing the project is in sales and their degree is probably in English Lit. Sometimes you get lucky and it is a construction worker. Their boss is the mayor's nephew and has the contract because of a rule that stuff used in local area must go through a local company. An example: a replacement part that we sold last month was for 2,200 dollars. The local company charged 11,500 for doing nothing except repackaging the part. A big fuck you to the Arizona tax payer.

All your infrastructure is using way more electricity than it needs. We can't get anyone to shift over to more efficient systems because that would involve effort on their part. We also can't get them to upgrade the service, instead we just have to find by trial-and-error what parts can deal with under voltage. Code has to be designed to deal with the frequent brownouts because no one wants to pay for a generator. Speaking of code the number of times I am asked to give people a printout of code is much higher than you would expect.

Global warming is ripping us a new one. Everything is flooding that shouldn't be flooding plus heat is everywhere. Waterproofing and heat upgrades are taking time because the original specs have to be updated. Which can't happen because they don't want to get the PE in to stamp it. Because that would make the project cost more eating into sales.

In short everything keeping you alive. Your water, garbage/recycling systems, sewage, trains, traffic signals, and roads was designed by better minds who are now dead. Everything now is a mixture of nepotism and short term self-interest trying to blindly copy what didn't even work that well to begin with under new conditions. If you want a job for life go work in infrastructure, if you want to be happy with your life go work in anything else.

Oh you might be wondering how is it we all haven't died from choleria and rabies infected garbage rats by now. The answer is simple. The very lowest paid people, the operators and maintenance crews, are actually good at what they do. Perfect? Hell no, however they get the job done. Which you wouldn't know given how hard the government is working to cut their pensions and not increase their salaries but there it is.