Well Google might be very kill-happy with their own products but at least they always give an early notice so everybody can at least take out their data and mov

Well Google might be very kill-happy with their own products but at least they always give an early notice so everybody can at least take out their data and move to another service. So even if they shut down Photo one day you will probably have time to download all your photos. Even today you can just download all your photos at once if you have already deleted them from your phone/computer. Btw you should be aware that if you bulk-download your photos from Google they might be in lower resolution and they will be missing some information (e.g. the geo-coordinates). So it might be a good idea to also store your (original) photos on your own devices.