Well I as a developer just want a browser which doesn't break existing features: localstorage, indexeddb were completely broken for months this year. Like CSS

Well I as a developer just want a browser which doesn't break existing features: localstorage, indexeddb were completely broken for months this year. Like CSS containment is feature that was shipped in Chrome in 2016, Firefox 2019 so how many years have to pass for Safari to implement it so it isn't just 'some new shiny' feature anymore?