Christ, it's not a fact, at all. We can sign players now and then have until the window closes at the end of August to release players via loan or sales - that's when we have to register our squads. That's the important date and in terms of people, squad size is arbitrary until that point. Even after then, you can have players that aren't registered to play in different competitions. City don't tend to operate like that but they are completely able to.
If any of our transfer plans are limited by Cancelo, Phillips and Gomez etc not finding loans, then it would be poor business (and unlikely).