There was Quelle, Europe's largest mail-order and retail company. They were excited about mailing their catalogue on CD-ROM, but slept on the Internet. In 2009, they went bankrupt.
Note that N=1 for the memory safety vulnerabilities they had with Rust, so the error of the estimated average number of vulnerabilities per LOC is quite large.
That's a good question! Especially after Frank McSherry's COST paper [1], it's hard to imagine where the sweet spot for Spark is. I guess for Databricks it makes sense to push Spark, since they are the ones who created it. In a way, it's their competitive advantage.