In some countries the terminals are not enabled for it. It’s not anything to do with Google Pay or Apple Pay, if a countries terminals don’t accept it, then you can’t use it. Pointless Google making something enabled that has no chance of working.
As countries change how they operate payment systems and interbank systems, things change and get updated. In Africa for example very few terminals are CDCVM enabled, as the banks only use a slightly different form of EMV chip which means they can’t use CDCVM so its not enabled.
Not every country offers the same banking standards, even in Europe, the banking system of the UK is very different to that of say Italy in how they operate.