Can we please start thinking rationally again?

[LineageRazor]

Every class, with the possible exception of CUL, needs materials produced by other crafts. This does NOT mean it is necessary to level every class.

Yes, materials produced by other classes are ridiculously expensive - but the thing is, YOUR class ALSO has materials needed by other classes, and chances are good that those materials ALSO sell at ridiculous prices. Craft and sell those, use the money to buy the expensive materials you need.

I'll be leveling every class to 60, but not because I feel obligated to, but rather because I enjoy leveling crafting classes. Prior to Heavensward, leveling other classes was obligatory, not because of the crafting materials they could produce, but because of the cross-class skills that they offered. In Heavensward, no class has any must-have cross-class skills. You can safely leave them at 50, sell materials your class produces at ludicrous prices, and use the cash to buy the materials other classes are selling for ludicrous prices.

[Jaeifer]

Every class, with the possible exception of CUL, needs materials produced by other crafts. This does NOT mean it is necessary to level every class.

Yes, materials produced by other classes are ridiculously expensive - but the thing is, YOUR class ALSO has materials needed by other classes, and chances are good that those materials ALSO sell at ridiculous prices. Craft and sell those, use the money to buy the expensive materials you need.

I'll be leveling every class to 60, but not because I feel obligated to, but rather because I enjoy leveling crafting classes. Prior to Heavensward, leveling other classes was obligatory, not because of the crafting materials they could produce, but because of the cross-class skills that they offered. In Heavensward, no class has any must-have cross-class skills. You can safely leave them at 50, sell materials your class produces at ludicrous prices, and use the cash to buy the materials other classes are selling for ludicrous prices.

Well put, that was something that I wanted to bring up myself.

People tend to think a bit one-dimensional and say it's extremely expensive to get materials because other crafts make them or that it's required to level up the other craft on the same level to advance.
But that's absolutely not true, we're tradesmen, ask each other for comissions - bring the materials for one of the mats from other trades, chip in a bit of gil for a commission fee since the other guy making you the material also wants to make a bit of profit and you'll have your material you need high likely still infinitely cheaper than market board and the other guy got some money too.

Case Example: Scale Glue

Scale Glue used to be like 50k a piece, while the mats for it are perhaps 2k gil worth of monster scales.
Lv60 ALCs with stats to reliably HQ them were scarce, so I had people come to me, I'd ask them for perhaps 5k per craft commission fee and I'd make them 30 Scale Glues HQ or howevermany they wanted. They got their 30 Scale Glues for 210k gil instead of 1.5 mil gil - I've made 150k gil profit - everybody's happy.

I'm an omnicrafter myself, I know the system will still live on and might see a popularity increase, but people showed me that it's possible to keep at it without becoming an omni themselves.
You don't have to be an entrepeneur for it - just think a bit different sometimes.