Well I'm no specialist and I don't want to spread wrong information here. There's more qualified people out there I guess.
But I remember is that the GPUs were considered as powerful enough only by the late 2000's. I mean to perform billions of calculations in real time or near real time.
The processing of that data is very expensive and Google being Google, they'll allocate enough ressources only if it's worth it (read it can bring a decent ROI or when people start making too much noise complaining about spam).
They could really easily get rid of most of the fake reviews. It's just that for Google it's not worth it.
But I remember is that the GPUs were considered as powerful enough only by the late 2000's. I mean to perform billions of calculations in real time or near real time.
The processing of that data is very expensive and Google being Google, they'll allocate enough ressources only if it's worth it (read it can bring a decent ROI or when people start making too much noise complaining about spam).
They could really easily get rid of most of the fake reviews. It's just that for Google it's not worth it.