I don't think I've ever seen a media article talking about what traffic controllers *can* earn which references a school crossing guard. That said, the reality is that base salary for traffic controllers is generally in the vicinity of $70k and, as you point out, it's the overtime and weekends that make it up to sometimes $3k/week ($156k/yr).
What your argument omits is that traffic controllers needn't finish school and can complete their training requirements in a matter of weeks. By contrast, for example, to become a paramedic requires (with, in a very small majority of cases, some exceptions) completion of year 12, a 3 year degree (with commensurate HECS debt) and a rigorous on-road transition training program. You then get to work 10-14 hour shifts outside in all weather, make complex life-and-death decisions (often alone) undertake hundreds of hours of CPD every year to maintain your certificate to practice (most of which duplicates the work you do and skills you use every day), pay back your HECS debt, and see things no human should ever have to see. And for that, even with allowances, extensive overtime and working up to 70 or 80 hours a week, you might just scrape into $90k a year. If the states can be bothered to adequately fund their ambulance service so you can get a job as a paramedic in the first place, which is a whole other issue all by itself. Similar goes for police, firefighters, nurses, teachers and more, and not all of those have the 'luxury' to top up their salary with large amounts of overtime.
Likewise, as per the original argument, ramp workers and others in the aviation industry are in the same situation as paramedics, if not worse (many aviation workers have trouble finding permanent full-time employment, for example), and are just as safety critical as a traffic controller.
I'm sure you can see more clearly which side the inequity exists on now. And no, I'm absolutely not trying to downplay the important role of traffic controllers.
I think you missed my point. I'm not making a comparison. I'm simply suggesting an article from news.com.au (yes, that is verbatim the $3k/week can be found) that highlighted one individual doesn't represent earnings in the sector. One person did well to get a higher rate of pay and then exploit that with dramatically more hours and overtime than is normal. This is not replicable as a generalisation whereas the salaries and hours you noted is replicable as a generalisation in those other sectors.
Rather than going down the path of what people can earn and the hours they can work, I prefer to look at actual data. The ABS Labor Market Insights data (a little dated sometimes) shows that only 48% of people employed as Road Traffic Controllers work full-time hours, median age is 45 years (significantly higher than the average). They don't have average earnings, but Indeed shows average hourly pay is in the low 30s per hour rather than the mid-40s that the lovely young lady in the news.com.au was earning. The ABS Labor Market Insights data shows that Ambulance Officers and Paramedics had full time hours, earning an average weekly earnings before tax of $2,333. Assuming the low 30s that Indeed mention (say $33), one would need to work 70 hours per week to do that (maybe 60 with overtime), yet only 48% of Road Traffic Controllers have full time hours. Doesn't seem that - as a generalisation - Road Traffic Controllers are going to be earning near Ambulance Officers and Paramedics. Given the general tightness in the labor market, it's unlikely that if they were all earning $3k/week that this wage would persist.
I do agree that there are huge inequities in the labor market at the moment. A challenge is that you can get a 187, 190, 407, 482, 489, 491 and 494 visa as a paramedics so labor supply can be fulfilled by immigrants, but that the old pathways for unskilled labor (like road traffic controllers) are still undersupplied.