I would say, with respect, I don't think this experience is normal or standard. I've never been reimbursed for a conference even if it was exactly for the technology that company built their entire product with.
My personal experience as a software engineer has been getting reimbursed for one or more conferences per year at every job. I've never had a software engineering manager say no to a relevant conference requested framed in a way that benefits the business.
I wonder if there's an aggregate data source available to see how common / uncommon this is.
Have your companies offered a general professional development budget?