If people acted ethically, it would solve most of my headaches. 

I started doing a regular routine of enzyme treatments every few months I use either Ridex or the enzyme sticks by Green Gobbler down each sink and shower every month or so and no problems since. 

Everything you just mentioned is a ton of work, and if you've got the work ethic to do that you could easily find something where you could make $40k-$60k+ by just shopping around for a better job and moving up in something.I'd even consider finding a Property Management firm to go work for and get some real world experience in this industry.

In 2011, the company who did the treatment had to return 4 times to totally get rid of them, but in 2017, only 1 treatment was enough. 

Most agents are not going to run away from closing a deal as long as it is done lawfully and ethically. 

If you are an NAR member, it is also a requirement per the Code of Ethics. 

I'm struggling a bit with this ethically.

I agree with you that seeing the industrial window is always best and yes window treatments can get really expensive.

About the only way you can do it is build in the county (not in a city), and when you do this you may be able to connect to municipal water but you will almost certainly have put in your own septic systems or sewer treatment, which gets expensive.  

These are professionals with additional training and a stricter code of ethics.