But there is nothing new here. Its not like developers avoided streaming assets and now somehow will do it. We have 7 years of Full hardware support in current gen consoles and plenty of games using it. ps4 - Partially Resident Textures, x1 - Tiled Resources https://blogs.windows.com/windowsexperience/2014/01/30/direc...
Then why do even modern games still use these map and character movement tricks? According to you, this problem should be solved!
Because its not solved. Games have only gotten bigger; assets are bigger than ever. Having a hard drive in every console actually helped a ton, because the hard drive/memory bandwidth is larger than the disk/memory one, but it didn't help enough.
There's no way around the fundamental bandwidth at the hardware: If a game needs a gigabyte of assets for the next major scene transition, it will probably need to use tricks to make sure that scene transition takes longer than, say, 10 seconds (50-100MB/s is a typical read rate). Checkpoints; stall sections which slow the player down; limiting the top speed of the character or (especially) vehicles; slow opening doors (think Dark Souls/Bloodborne); vestibules between two doors with an adjustable length based on expected load time... They use technical tricks on the hard drive, copying commonly used assets all around the platter to reduce seek times. I've even heard it said by a developer that "we'd be fine in this transition if the game gets installed to the inner edge of the platter, but on the outer edge the load will take too long"; that's how close modern games run against hardware limitations.
The software in play hasn't changed. Duh. We're not talking about the software, we're talking about the SSD.
Here is another example, 6 year old Far Cry 4 with custom implementation https://www.youtube.com/watch?v=SVPMhGteeuE