Coming back to the map markings. It is also economics. How many players are going to use the feature versus how much work it is. It migh seem simple thing, but when you add option for player to write on the map there are lots of things you need to take in to account.

How many symbols can be used, what happens if the games resolution is changed from the settings, how the text wraps if its close to the edge of map, what if there appears new automatic map marker under text user has wroten, are there interactive symbols for fast travelling or something else, will those go under the text or on top, what if writing uses special characters etc etc. Not to mention if devs have been cute with the map and its not just a flat texture. Skyrims map for example is the game world and you can see storms on it. Spending time to make and test all those features when it really serves a tiny fraction of the playerbase is wastefull.

About saving the game. For better or worse its also a game mechanic and now days its not necessary about the limitation. For example if you could save in a middle of an battle in pokemon you could just save the moment you start a fight with shiny pokemon and you could infinetly try to catch it without any stakes. Or if you could save in middle of epic multiphase jrpg boss it would take away from the feeling of succes after long battle.

But i absolutelly agree games should atleast have exit save, so if real live happens and you need to close the game, it should not punish the player and loose their progression.