Started as a 3/3 mage, and even today my magic skills are much higher then my others - well, except lake forage, which slowly climbs to 150 due to the ammount of harvesting and crafting I do lately
But I started as a pure mage, only meleed a bit on starter island when I wanted to do something different than throwing acid and ice at all the critterts. Even today my magic skills greatly surpass my melee skills.
145 elemental mage, 155 healer and only 85 in melee.
You can infact generate nice income even with elemental, just go and find some things that you can easily kill in one-two (but preferably one) hit - carnivores are preferred since they drop much more stuff then herbivores.
Sure, foraging - and crafting - is the big money maker, but you can make nice summs even with just hunting. You just need something that give you nice ammounts of stuff - the higher level the more it's worth - and as fast as possible.
Early on being a melee fighter is easier than being a mage, but this will change soon (don't remember the level when they get equal atm) and at lvl100 when double-missle plans become available to you, you will greatly outdamage any melee fighter at the same level.
However as others said, you will need hp on higher levels firstly due to the increased sap and hp requirements for double-missiles and generally to be able to take more than 2 hits from a mob
Jewels help with hp ofc, but leveling melee helps aswell.
Edit: One downside of magic vs melee is that mages aren't built for damage absorption but damage output so wandering around in light armor can be more risky that in heavy. Mages are more prone to surprise attacks than melee warriors since when a mob hits you there is a chance that your spell incantation will be broken.
Hope this helps