They could in principle. GCP, for instance, does do that. So does HP. And Databricks don't mind that as they have a strong open source legacy. But that takes away the proprietary lock-in strategy of Snowflake.

Delta is open source, but Databricks keeps optimizations for themselves as proprietary. I'm not sure why it would be any better than Snowflake's solution, which is automatically deployed across multiple AZs as a fully HA system and gives full ACID transaction compliance across any number of tables (not just per-table).

Essentially with Databricks making Delta open source, you can move away from Databricks to EMR or Presto (with their own optimizations) without incurring a data tax. You're also able to move between cloud providers at ease as data sits in low cost buckets.