30 meteorite ore for 1 RP = 27 RP to transmute ONE legendary card...

[StanislavOZZO]

Meteorite rewards in the quest trees are extremely low. I just uncovered a full tree in one go and got barely enough to transmute one legendary card. =/
And with daily quests even if I reroll to get 2RP every day, it's 14 quests to get one legendary transmuted.
Greedy It will take forever to transmute the cards with you.

 

[Lexor]

One of the reasons why prestige levels are here. More RPs, more MPs, more premiums.

 

[StanislavOZZO]

One of the reasons why prestige levels are here. More RPs, more MPs, more premiums.

Getting to Prestige 10 will take another forever

 

[Lokiat0r]

Getting to Prestige 10 will take another forever

Yep. I've just about completed prestige 5, and that's taken almost 600 hours.

As far as I can tell, prestige 5 is the point where you start gaining lots of powder. By the time I reach it, I'll nearly have a complete deck with most of the premium common and rare cards. So the bonus premium in the first four cards is effectively 10-20 powder per keg. And really, every prestige level reward at this point is one that effectively gives quicker access to more powder.

EDIT - On the plus side, I've noticed that the newer expansion trees don't include scrap nodes. Lots more powder to acquire!

 

[StanislavOZZO]

Yep. I've just about completed prestige 5, and that's taken almost 600 hours.

As far as I can tell, prestige 5 is the point where you start gaining lots of powder.

"Lots" is relative. Yes, you will get some more powder now at Level 5 and it's a decent achievement. Yet in the grander scale of things this addition will not make a big difference in your powder gain.
Also to keep in mind, each new level takes progressively more time. I am now at Level 9 and just under 2000 hours of play.