I have your exact setup: RX480, 1440p 144Hz FreeSync monitor (Samsung C27HG90). I bought my RX480 a year before I bought my monitor, which is why I'm not running a Vega56 (which is what I would've chose if I bought my monitor and GPU together)
1) Yes, the RX480 requires some settings tuning to hit >60fps on today's most demanding games, but there are plenty others that it will push >100fps on high settings.
2) I have yet to play a game that my RX480 can't handle at >60fps at medium-high settings.
3) I can never tell the difference between "high" and "ultra" settings.
4) Games are either going to look amazing at medium-high to high settings or they aren't. Going to Ultra doesn't change the artwork and level design of a game.
5) If I need >high settings to enjoy a game, the problem isn't the visuals, it's the gameplay
6) Yes, it sucks that Nvidia continues to pull away from AMD on the high end GPU arena. That said, I'm not sure it makes sense to get a Vega56 right now at >$450. You'll have your monitor for...6 more years(?), maybe more. What's another 6-8 months on your current GPU until next-gen AMD? If you buy a high end Nvidia card right now, you're going to be VRR-less for another 2-3 years while you ride out the lifespan of that card.
7) A GTX1070Ti or GTX1080 might give you high enough fps to overcome the benefits of VRR now, but what about 3 years from now?
8 ) You're going to have to spend $100+ MORE on an Nvidia card compared to a decently priced Vega56 to give you enough overpower to overcome the benefits of VRR. Worst case, maybe just search/wait another month or two for a good Vega56 sale price.
9) The Nvidia RTX2080 will initially launch according to current-gen price-performance structure, especially since it's only competing against Nvidia's own GTX1080, they have all the time in the world to sell off existing stock of GTX1080's at current prices. After that, when RTX2080 prices start to drop, Vega prices are going to have to decline to keep pace.
10) Have you looked on Ebay? Here in the US, it looks like you can land a used Vega56 for $375
Main: i5-3570K, ASRock Z77 Pro4-M, MSI RX480 8G, 500GB Crucial BX100, 2 TB Samsung EcoGreen F4, 16GB 1600MHz G.Skill @1.25V, EVGA 550-G2, Silverstone PS07B
HTPC: A8-5600K, MSI FM2-A75IA-E53, 4TB Seagate SSHD, 8GB 1866MHz G.Skill, Crosley D-25 Case Mod