1. Fighting games are different online and offline.
1.a. Casuals who play online experience difficulties that are in part due to their skill level, which is influenced by their lack of offline experience, and in part due to online latency forcing them into bad habits, or those who have good habits will experience the latency in their own way.
2.b. Pros who play both offline and online are aware of these discrepancies and awareness helps you overcome or acknowledge issues and either work around them or accept them as is.
2. Fighting games are vastly based on shifting meta and are no less grindy than mmorpg or moba, except the "xp" here is that you need to get a feel for your character and the entire cast so that you can learn.
2.a. Your level of skill is directly influenced by the skill of those you play. If you never face a vortex you will never need to worry about it. If you're a casual put in the blender of a pro, you have little to no chance of winning.
2.b. Pro level of skill, thus, is a result of meta and of high level players "grinding one another" as well as having ample knowledge to apply in the lab and develop situations and technique for themselves and the community.
3. The above issues are more the source of Injustice 2 being poorly represented and called out by so many people than zoning itself. Zoning is an easy way to avoid "honest play" but it's not a necessarily bad thing, as workarounds always evolve the meta and strengthen the high level play as a whole.
3.a. Problem with zoning begins with online being unforgiving. For example, when I play Starfire vs a Supergirl if I try to zone I'm literally free to her teleport. I labbed it, I still can't respond in time a lot of the time or I don't respond correctly. I'm casual.
3.b. Problem with the meta is not that it's stale but that there is no reason to evolve it because the community, pros and casuals alike, were conditioned into discarding nrs games based on lifecycles, poor communication from the company and the knowledge that beyond a certain point no matter how broken something in a game is, (coughmkxjasoncough) it will not be patched and the game will become abandonware.
The community is waiting for mk11 so the meta is not really showing any massive evolution anymore, save for potential fans with private scenes who may do so at their own discretion but not as part of the community at large.