I'm not saying Apple themselves have shunted the developers, I'm thinking that the developers themselves have moved jobs of their own accord since they see no future in macOS. It's been obvious for a while now that Apple only considers iDevices as their money-spinners. Their actual computers have been long neglected, and their updates for the last several years have been to include more iDevice-like features, so I would think the macOS developers would willingly believe Apple themselves aren't wholeheartedly behind maintaining their desktop OS. It just feels like there is very little willingness from Apple to build a good desktop OS any more, and no sense hiring macOS developers as a result.