Salesforce's Dreamforce conferences are similar. There were 120k attendees the year I went.
No developer (or not a lot) would knowingly choose Salesforce as a tool, yet all these folks are at the conference because the employer paid them to go.
I don't think that comparison is really valid. I know tons of companies that run virtually all of their CRM on Salesforce, and this isn't going anywhere soon, nor do these companies have anything that they are planning on transitioning to.
With Oracle, though, I think it really is a lack of technical positioning rather than any "devs hate them" sentiment that is a real existential risk to them long term. Lots of senior execs realize that Oracle's cloud technology is a joke, and more importantly their crazy licensing model makes it a major PITA to run Oracle DBs in any other cloud, and perhaps even more importantly that a lot of changes in dev architecture are making the huge, powerful, monolithic database less critical than it once was. Sure, there are lots of legacy mission critical apps that live and will live on Oracle for a long time, but executive leadership at many companies is now starting to see this (appropriately IMO) as a competitive disadvantage, and they will make choices to try to extricate themselves from Oracle as much as possible.
No developer (or not a lot) would knowingly choose Salesforce as a tool, yet all these folks are at the conference because the employer paid them to go.