Ayup, widely known yet not consistent nor truly worth the effort for $200 steerage seats. However, significant differences can exist for pricier flights when pricing high-priced seats with the same airline, partner airline (OneWorld, Sky, Star), or even flight search company's websites in different countries, e.g., Expedia US vs Expedia HK.
Passengers booking flights with 3rd parties, e.g., Kayak, Expedia, Skiplagged, ctrip, et al have shiftier ground to stand on versus people holding tickets booked directly with airline A or its' partner airlines. Is saving $50 worthy of being low man on the totem pole?
Leveraging a free or nominal fee VPN is one thing, but being able to read different languages, utilize currency arbitrage, etc. helps. Rate differences may occur by language and currency. And sometimes, info is simply updated faster/slower on different sites.
Setting aside the prior info, some of the biggest rate differences experienced are between 2 partner airlines for identical flights, e.g., American vs Cathay Pacific, BA, et al; United vs Air China, Lufthansa, et al; Delta vs China Southern, KLM, Air France, et al. Particularly if a person holds significant rewards points or is paying a few to several thousand for seats closer to the pilot, this can be worth some extra effort.