It happens to be right next to the DOE sponsored Frontier Observatory for Research in Geothermal Energy (FORGE [1]) site that established the temperature and ability to create permeability at depth using EGS.
Op is really just describing a core breakeven metric on the energy source. In the same way you measure an oil well with half-life of useful output, this is basically saying "EGS can prove to be useful if they can make sure they extract more economically useful heat than the economic costs of constantly drilling new wells."
Since no one has really made EGS widespread yet, that suggests no one has yet cracked this nut.
Theoretically, a leak into groundwater aquifers would make keeping the system pressurized harder or would dillute the amount of heat they're extracting, so seems like a stronger commercial incentive not to f up the groundwater.
In oil fracking they're just trying to pull the oily goo up from underground. And in theory you could do heat extraction using just water instead of shale goo solvents so any contamination would be less impactful?
I dunno, I'm just internet armchair quarterbacking this until a real geologist chimes in, but I can see how this is a somewhat different beast that shale fracking wells.
There's a geothermal project at the Newberry Volcano in Oregon that also looks interesting (different people doing that).
That seems like a fallacy.