Nobody can come up with an alternative. the only people who are experts in something are people who could be good in either a regulatory role or a business role. Thus there is and always will be a revolving door because when one side decides they need more experts the obvious place to look is the other side of the door.

Note that without the revolving door both sides would be worse off. (Unless you take some other action to mitigate this - I can't think of anything but there might be a complex answer)

There's a lot that could be done.

One of the reasons DARPA program managers sit a fixed term is to precisely prevent careerism and castle building. The reason members of congress have a staff is to support them in researching topics.

But ultimately it comes down to the public, being informed by media, holding politicians responsible. I may disagree with portions of Bernie and AOC's political platforms, but one thing I don't have to worry about with them is that they're in the pocket of a company like Boeing.

We get the government we ask for. Want better? Raise your expectations and vote accordingly.

Sure, you don't have to worry about Bernie or AOC being in anyone's pocket, but the only thing they're experts at is getting elected...

Another approach could be sufficently good communication. If you need former experts in writing the regulation to be compliant or need to work in the industry to know how it works enough to regulate it implies that the communication on both sides is missing crucial information.

The process of doing so and ensuring it would be very laborious in that you would have to document every last detail, go through and make sure they were covered, make sure they were retained, and make sure that their understanding of every last detail is identical. Making matters worse is the mix of implicit and explicit. If you use a sprocket on something the design implicitly states "Do not allow it to rotate that way!" An added strut on a panel already more than capable of supporting itself and the rest of the structure may be redundant or needed to shift resonant frequencies into a range where they would be irrelevant.

No, to write the regulations you need to understand the problems. The people who understand the problem probably started in industry.

Indeed, and there are plenty of people in the industry who understand the problems and want to do the right thing. These are the people we need to give a voice to. People who understand, for example, that the arguments for not informing pilots about MCAS were self-serving sophistry with no technical or human-factors justification.

I don't think it's necessarily an accepted business practice, but a known failure mode of our regulatory model.