This is the type of critical thinking you should be doing on your own before making the claim that mobile champs just have this massive leg up on immobile champs.
It's obvious. Let me break your bullshit down point for point:
Stunning projectiles come from a distance. Many champs that are mobile don't have massive ranges to fight back with, so they have to stick their necks out more than, say, Anivia or Veigar have to.
The stupid amount of mobility allows for them to not need range on anything. So, The Range in this case = 0 advantage while the mobile champs get an extra advantage of being able to be where they want to be.
Stuns/Snares may not do damage, but they're hit confirms for moves that WILL do a lot of damage. Lux's Q isn't deadly because it does 1/2 your hp. It's because she's going to E and ult you right after, which will do 1/2 your hp or more.
Again, when a champ is mobile they have the advantage of easily staying out of range of stuns/snares while then being able to move into range when the time is right. Advantage mobility, with disadvantage to immobility.
Mobility champs use dashes to get out of jail. Champs with stuns and shit use their stuns and shit to get out of jail. What's the problem?
The problem, again, is fucking beyond obvious. Mobile champs can use their mobility to avoid stuns or wait for an opportune moment to strike. An immobile champ DOES NOT have that option. Another clear and ridiculously obvious disadvantage to immobile champs.
Many immobile champs have better scaling than mobile champs in general. When you need a bot lane mage, you don't pick Ahri. You pick Vlad/Swain/Brand. Hell, even Morgana, who's also immobile. In the pro scene, we see Talon show up in the mid lane, yeah, but we're seeing Orianna, Ryze, and Zoe, all champs with no escape tools.
A. This is not realistic. Most of the new champs with high mobility have more scaling than they should have. The reason you don't pick an Ahri bot lane is b/c she has less utility to protect the adc than someone like a Morg has. Brand's issue is not his scaling, but his base dmg, I'm pretty sure a Rioter even admitted this recently. Also, Zoe certainly has mobility once she starts snapping up summoner spells.
B. Even if this were 100% true, which it's not, it has nothing to do with the effectiveness of mobility. Mobility VS immobility gives a clear advantage to the champ with the mobility. It allows them more tools to decide what to do or what not to do and gives a clear tactical advantage in the ability to make that decision VS needing to constantly be aware of the positioning of your own immobile champ and every other mobile champ.
In conclusion extreme mobility of so many champs has fundamentally changed the way the game is played and I'd argue that it's changed it negatively. Positioning and champion strengths matter much less for the mobile champs and are basically irrelevant for the immobile champs. Positioning and understanding champion kits was a big learning curve and an important part of what made League so fun to play. A lot of those interactions are gone now thx to some idiots deciding to continuously release broken shit. THIS is the type of critical thinking needed to understand why your points lack any sort of realistic critical thinking.