1. Can't you? I've levelled fishing all the way to 48 without gathering gear. I know that you get less hits per node with bad gear but what I said in my post was you get the same items.

I don't care so much about getting 1 or 2 less hits per node when I have a chocobo to get me from A to B rather quickly.
2. It was mentioned in the 1.19 patch notes that certain materials like gold ore will return from patch 1.21. Where are they going to put these without upping the level cap? It makes perfect sense for gold to be the next tier metal above cobalt. It would be a waste to cram it into the same level range. Of course only SE knows for sure what their plans are but I would not be surprised at all if the cap goes up in February.
3. I am a crafter/gatherer, I'm sitting here with well over 400 million gil, you don't get that without being a dedicated crafter/gatherer. Yet I am still strongly against these. I made a lot of gil logging back in the summer on grade 4 in Cedarwood. While that would have earned me the grade 4 achievement for La Noscea it would not have earned me any of the others. A real gatherer will gather the materials they need or want to sell and there is absolutely no profit to be made by going back to a lower grade in 90% of cases. Grade 4 logging being a better money maker than grade 5 was an exception rather than the norm. As a miner I only ever mined grade 5 once I hit 38 because it was stupid not to. Likewise with crafting, I'm not going to make any gil by producing 1000 rank 30 items, I'm going to make gil producing +3 end-game weapons or similar. There is no incentive to produce gear no one wants unless skilling up. There's a reason I NPCed about 1000 yew half masks/silver rings etc. back in the day rather than selling them. I'm almost certain by GSM and CRP would have these achievements if things counted. I can't say that for my others because the progress was mostly leve based and in a lot of cases after the massive EXP boosts. But it doesn't take a genious to figure out a formula to credit people based on when they reached rank 50.
4. You probably have a point there but my point still stands that it would be stupid to do this on a character with all 50s when you could end up with two characters with every class at 50. Crafting and gathering is not fun in its current state, no one wishes to repeat a year of that. I can only tolerate grinding crafts via leves these days because it's so painfully slow to do it without leves, something you'll have to do to get these tools. Since you love it so much perhaps you can log into my account and get my tools for me too.
5. There's better ways to make an achievement difficult to get without making it the least form of gameplay imaginable. Where's my achievement for making 1000 HQs? Far better than endlessly grinding no? The achievements aren't even difficult, just time consuming. Time sink != difficulty.
6. I believe I already covered this in 3.