It certainly took me more than a year after I had started trying to get the vouchers for all the stations and I did this completely by myself. But I didn't do it just for myself. My intention was to help a small streamer make her little guild a bit more attractive for others to join.
It was all in vain, of course, because by now only one player from those days can still be seen in the game regularly and everybody else left. Even the streamer only returns for the new chapters.
For me, making the grandmaster stations only available to grandmaster crafters is a bizarre idea. First, the motivation appears to be rather mean-spirited. And second, I believe it is rather pointless anyway because the people actually using a grandmaster crafting station are very likely to be master crafters in the first place, especially considering the fact that motif knowledge is counted across a player's entire account and thus the most expensive of the required achievements isn't as expensive anymore as it used to be when I and most likely many other crafters had to hunt down missing motif pages in our beloved decentralized guild store system.
Without a purchased copy of Summerset or ESOPlus, you can't access jewellery stations for anything, regardless of what traits that you may have learned if you had a previous subscription.
Yet you can go to another player's home and have access to all crafting tables for every other Chapter that you don't own. You don't even have to do any work to have access to them. Some guild members may have contributed; most won't have.
But yeah, why should players that don't have GMC have any access to this station at all? Why should players have access to any tables where they haven't paid for the zone access?
Alternately, why can't I use jewellery crafting stations?
It's all a bit unbalanced.