The obvious question

Stuff reports that housing speculators aren't paying their taxes:

Speculators are making millions in an overheated housing market but as many as one in four didn’t pay the tax they owed on properties flipped last year, IRD figures reveal.

Of the 1701 property sales subject to the bright-line test in 2019 – a form of capital gains tax – just 1285 have paid up.

That’s a compliance rate of just 75 per cent, meaning one in every four speculators the tax applied to, hasn’t paid yet.

This is tax evasion. Tax evasion is a crime. So why aren't these people being prosecuted for it?