What makes you believe that this is the case?
The information that was intended to be collected with the ETA can easily be collected with the application for the TDAC, plus additional information that is necessary to determine whether the applicant is liable to pay the tourist tax.
The TDAC is precisely the way that has been found to implement the tourist entry tax, in addition to the information that was earlier intended to be collected with the ETA. In other words, the TDAC combines the abandoned ETA and the tourist tax collection.
See this extract from the news article:
It couldn't be spelt out more clearly.
We must be patient and see how this is going to be implemented if they will ever go through with it.