I feel like Apple has decided that a reminder is for something to be done NOW (or in 5 minutes max) and doesn't want people postponing reminders in, say, 15 minute increments. If a reminder pops up, a user can only choose between 'mark as completed', 'remind me in 1 hour', or 'remind me tomorrow' with a hard press on the iPhone 7.
You can only push the reminder to 5 minutes over and over, or push it a whole hour and risk not getting to it in time: This has obvious implications: if there's something you want to do in 15 minutes or 30 minutes, you don't have that option.
On the flip side, if a reminder alert pops up on macOS, one only has the option to snooze it for 5 minutes, 1 hour, or until tomorrow, with nothing in between. If a calendar alert pops up on macOS, we're presented with some quite usable snooze options: 1 minute, 5 minutes, 15 minutes, 30 minutes, 1 hour, 2 hours, 1 day, or 1 week: This is an issue I've faced for such a long time on both macOS and iOS, though for the purpose of this question I'd like to focus on macOS as that is where, I hope, manually editing settings files might even be a possible solution to this problem.