Yes, opening or resuming huge apps/games will require time, there is no magic solution. At least the time required to resume the current game/app (dump it to a file) and to resume the other one (load the file into the memory) plus probably adding some compression/decompression if unlike these next gen consoles they don't have dedicated hardware to do it on real time. In PS5 this means a couple of seconds to resume a game, same than loading it but with the difference that you'd skip menus or loading screens and would return to the same point instead to the most recent checkpoint. To suspend a game and launch or resume other one probably would that more than the double of this time (probably around these ~5/7 seconds we saw it took to move from Sackboy to Destruction All Stars in the PS5 video because writing speeds are slower than reading speeds in SSDs).
I'm not a OS coder right now, but did study OS programming as part of the Computer Science degree in the university and the high school and programmed OS stuff there. And have close friends working in many important game studios, including the ones who made the PSP or Vita cameras, or the ones who programmed one of the Kinect games shown on its E3 reveal, or the pioneers who first made geolocation games or AR games like Pokemon Go many years before it, plus many super talented coders in AAA games from several companies working on next gen games or some of the biggest mobile games ever, just to name a few examples.
Tell your boss to calculate time spent in salary for people waiting to open apps in a month from all your coworkers and then calculate how much they'll save in salary if upgrade all your computers to high end PCs with super fast SSDs buying one as a test. They will see the huge productivity increase and money saved for the company and will buy you all a high end PC with super fast SSD. Same goes with replacing VS with another faster IDE or at least text editors. This highly increases the productivity, and this is why most gaming companies do it.
Yes, to be able to suspend a huge app like a very long render and to resume it later would be useful to increase productivity too in some cases. But you can also use these waiting times to do other tasks like read the mails, the tasks in Trello or similar, bugs in Jira or whatever you use, take a break to have a coffe or go to the toiet, etc. Regarding big renders, to increase productivity more there are options like render farms with things like Jenkins and so on (the idea is to 'outsource' your animation rendering workload distributing it to several computers of the office so they use idle times to help someone else to do big render tasks as a background app that only uses free available resources).
Yes, I assume in Xbox they are dumping the memory that every game use instead of the whole chunk of memory available for games. So the more memory that game was using when suspended, the more time will require to resume or to suspend (I assume that when possible they will do that suspending process in the background). I'm pretty sure they did show it with BC games instead of with AAA native Series X games because next gen use like 2X the memory so should take longer to resume. But if they didn't optimize it too much or want a simpler solution that would work for all cases they'll 'simply' dump the 13.5GB (less in BC games) fixed sandbox area of the memory available for games plus some registers from CPU, GPU, etc. instead of only the memory allocated for each game. Obviously they work with virtual adresses and pointers, and the game isn't always in the same part of the physical memory. I already write too big walls of text, so didn't go into detail to don't make them longer, and to keep it simpler so more people can understand it. Obviosly it's more complex in many important 'details' but that is the main idea/concept.
