I was a bit confused by what you meant by this because at first I thought: There is an excuse, namely that they are not legally required to.
I don’t see a major problem with changing the law to require super payments to be made in lockstep with salary payments - as long as it is phased in / with advance notice.
Hmmm. I think it depends on your perspective. 
Some things are more complex now that we have superstream.
The bottom line though with superstream is that it should mean that there is an independent party monitoring for when a company misses its first super payment (as well as monitoring by government). That doesn’t exclude completely the possibility that employees are out of pocket but it minimises the losses to one payment period - and that’s a good thing.
One additional observation on superstream: for some small and medium-sized employers, there is a cost per transaction in using superstream. Hence, forcing the company to make super payments in lockstep with salary has a real and measurable cost.
To elaborate on that, if an employer is using the government-run Small Business Superannuation Clearing House (SBSCH) then I believe there is no transaction cost but then of course there is only one set of eyes (the government) rather than two. There are eligibility requirements that an employer has to meet in order to use the SBSCH.
A large employer, who won’t be eligible to use the SBSCH, will choose a plan with the superstream provider that is more suited to a company with a mass of employees and a mass of transactions i.e. not a plan that hits the employer per transaction (but more likely a fixed large charge per period).
That has a real cost though. Imagine that I just became an employee of company X. If I stay 10(?) or 15(?) years then I will be entitled to long service leave. So are they required to put money away incrementally, and lose the use of the money for a decade or more, on the off chance that I don’t move on before reaching that entitlement?
Same issue with termination payments. It would tie up an unreasonable amount of cash (in my opinion) if a company had to make financial provision for making its entire workforce redundant at any time.
The situation with annual leave is not as dire but I know some employees who never quite take their annual leave (always something important going on) so that they could be several years behind.
So there is room for argument about what is an actual entitlement (you’ve done the work, you are entitled to be paid, and super on top of that) and what are accruing entitlements, some very theoretical.
The starting point would simply be to legislate to require an employer to show in its accounts its provisions for employee entitlements and have that audited as reasonably and correctly calculated. Since every company is required to form a reasonable belief that it will be able to meet its financial obligations as and when they become due, a company that is in real strife will be detected sooner.
