Google internally announced a while back that Bigtable (which powers Spanner etc.) hit 1B queries/second -- there definitely exist systems with far larger scale (though admittedly this is with lower atomicity requirements and probably includes reads etc.).
VISA does 500m+ transactions per day and Spanner does 1B queries per day, but it's quite unlikely that what a transaction means on VISA is the same as what a query means on Spanner.
The hardware in your flat definitely cannot do 1 billion queries per second -- that requires a massive, global system, which can probably also support a shared system with ~100,000x less queries.
Visa claims 24,000 TPS, but in reality runs at a 10'th of that. It would be interesting to see if Spanner could process the same 2,000 transactions per second. Sqlite definitely can't.
