Your big problem here, I think, is assuming that a movie based on these games would literally be a retelling of the game's story. Honestly, the best video game adaptations (admittedly not a high bar) are the ones that deviate most from the story and use maybe some of the same themes, visual ideas or characters to tell a completely original story.
In a sense, I think this is why it's so hard. Fans get pissed off if anything changes, but for the sake of making an interesting and compelling movie things have to change. You can't recreate the genre conventions of a movie in a video game without losing something in translation, and the same is just true in reverse.
But really..
10. How does any fantasy movie explain its setting to the audience? Heck, how did lord of the rings do it? The trick is the proper use of film language and precise, controlled exposition and keeping to a relatively simple story. Lord of the Rings never sits its audience down and explains to them what hobbits are and why they exist, it shows you hobbits and establishes everything the audience needs to know about them using film language. Within a couple of minutes of the hobbits being on screen, the audience already knows what hobbits are like.
The elder scrolls is more complex because the identities of all the species are less clearly defined, but ultimately the same rules apply. The audience doesn't need to be told the full story of the world, it just needs to see it in action.
9. While I will never understand the inability to accept that Half Life is dead, what exactly is the problem with making Gordon Freeman talk? I'm going to be honest, I always saw Freeman's silent protagonist status as a mistake which very quickly began to hold the story back. In Half Life 2, let alone the episodes, it's become very clear that Gordon Freeman is a character, not an avatar. He has a backstory, he's done things in his life which are distinct from the player controlling him. He graduated from MIT with a PhD in theoretical physics. He has relationships to other characters which predate the player's interaction with him.
The idea that giving him a voice or personality, particularly in a completely different medium, would be sacrilegious strikes me as overblown. Gordon Freeman is just a character.
8. At this point, Bioshock is a set of themes and recurring plot points, not a setting or a story. As the Elisabeths put it, "a million million worlds, all similar, all different, constants and variables ... there's always a lighthouse, there's always a man, there's always a city". Bioshock is an anthology, in effect. You wouldn't need to retell the story of any of the games, just make a new story in a new world with enough similarities to tie it in with the bioshock multiverse. Considering how cinematic Infinite in particular already was, I really don't see the problem.
7. Agreed. Nope.
6. I think maybe it could make an interesting anime, but a movie.. I'm not seeing it. So much of the Zelda games is the artstyle and distinctive look of everything, and seeing that recreated in a live action film would either be jarring or uncanny.
5. Name one military science fiction film which was actually good (Starship Troopers doesn't count, it's a parody).
It's very difficult to carry a movie with stories about generic soldier men doing soldier man things but in space. That works well in a video game because you're not meant to care that deeply, and it works well in books sometimes because books have more time to explore character motivations without needing to show them on screen, but movies need to be economical.
4. Not a series I know much about, and I'm included to agree.
3. Now this one, I can actually see working, essentially on the level that the Fast and Furious films are already basically GTA movies and have always made mad cash. Just make a bunch of overly macho nonsense about big men driving fast cars and doing crimes and market it at teenage boys using the recognisable GTA name to create brand recognition while carrying over absolutely nothing from the games, and someone could probably make a lot of money.
Neither of the top two are series I know or care about, so I'll take your word on those.
