Even still, Google Flights (and of course, old ITA engine underneath I guess) completely redefined the speed you expect of having pre-fetched flight availability and pricing data to be able to quickly search through. I guess this kind of being able to quickly find the date/price/cities combinations you want just isn't a priority for most airline software teams. (or Amadeus/Sabre)
The GF speed is there is I turn off NordVPN tracking