This isn't a concept Legion introduced.
In WoD it was your legendary ring and returning players were limited by the entire questline to unlock as well as your weekly +3 upgrades from Archimonde. Yes they later made it so you could speed it along with valor upgrades but prior to that it was at least 20+ weeks to max your ring just from that stage alone.
In MoP you had your legendary cloak which also was an incredibly long time-gated quest chain.
In Legion the only thing limiting players from capping their artifact weapons is either AK level or their lack of putting in effort. There is no cap to how much AP you can farm a week so if a player really wanted to max their weapon in a very short time it is entirely possible. Same for gearing in general, you can run as much M+ as you want for gear upgrades during a single week.
The only negative difference is that NH is less about gear and more about skill. This is a reality players don't want to admit. If they're wiping or not progressing it has less to do with lack of preparation and more to do with lack of execution. Players are expecting to trivialize NH with gear and it's not going to happen at least till 7.2 traits make it more of a possibility.
edited: grammar