It's part of the enshittification cycle. I'd been a Nikon camera user and figured I'd upgrade...reviewing Nikon, Cannon and Sony, the new startup...Sony was the only body at that pricepoint that also had a motor in the body to let older class have auto-focus...that was a feature the other two were gatekeeping at higher priced bodies.
Now that they're established, its time to chip away and add shareholder value.
The classic walled garden approach - make everyone buy lense mounts that only fit their cameras, people collect lenses for their brand of choice, then make them regret ever making the purchase by racking up subscription costs and introducing 3rd party spyware to sell your data. Sunk cost fallacy makes people eat shit because they're already too deep. Capitalism at it's finest.
Now that they're established, its time to chip away and add shareholder value.