Things started to change in 2007 when the ATO started to offer a...

Things started to change in 2007 when the ATO started to offer a pre-filling service for individual tax payers.
As time has gone by the ATO through Government legislation have required reporters of this information about taxpayers to do so in a more timely manner.
They are also required to report more information from more sources.

Bank interest. If you don't quote a TFN then tax at the highest rate plus medicare levy is witheld by the bank from your interest payments.
Health funds have to report their clients details.
Property dealings are reported.
Wage and salary details reported by employers.
Centrelink report to the ATO about their clients.
For instance shareholders will find that the ATO can pre-fill most of their dealings with shares, dividends and franking credits.
The amount going through a retailers EFTPOS terminal can be compared to declared income.

Legislation was introduced requiring third party reporters to report in a more timely manner and in a format more easily integrated into the ATO systems. Their data matching processes are being increased all the time.

As far as the ATO is concerned developing a robust third party reporting regime will over time force more compliance with our self-assesment tax regime.

This is another step towards their goal of making sure as many people as possible report all their income.
As it stands many people don't do that but in many cases it's not deliberately fraudulent.
So the ATO or Centrelink send out letters and invite people to repay what they owe without penalty thus recovering payments.

Presumably this task force is meant to send a message to fraudsters. You will need to be more clever or we will catch you and punish you for committing fraud.

As an aside the ATO were told to go easy on businesses for a while after the GFC if they were late with their payments. Businesses whether they needed it or not were given some extra time to pay to help with cash flow, without incurring penalties.
That didn't last too long as the ATO soon reverted to being a particularly aggressive creditor tasked with cleaning up and tightening up the collection system.