blueglassfish

That's a respectable amount for a DW, true. Spark and it's ilk are designed for much larger scales though. Multiple FAANG use cases for Spark are in the petabytes per week range.

I’m not sure this locks anyone in. The APIs are open and Spark code will run on, say EMR, just fine.

Every vendor, be it Snowflake, Databricks, EMR, Athena, BQ, … charges for use of the engine. The difference with a Lakehouse is that one doesn’t have to pay the vendor for the simple ability to use the data with another offering. That’s what you have to pay for with closed systems, whether it’s data on the way in or data on the way out.