I don't know if you have given it any thought, but as level 20 dragons are referenced to in posts here, I took a moment and did some calculations on what is involved to get a dragon to that level.
Level 20
----------
15-16 = 81,920 x 4 = 327,680 treats (amt req to move from level 1 to 15!)
16-17 = 163,840 x 4 = 655,360
17-18 = *327,680 x 4 = 1,310,720
18-19 = 655,360 x 4 = 2,621,440
19-20 = 1,310,720 x 4 = 5,242,880
-------------------------------------------
Total = 10,158,080
Errata:
0 Requires $507,904,000 in gold coins
0 10,158,080 treats would move 31 dragons from level 1 to level 15
I don't know about you, but I simply can't relate. I considered bringing one dragon to level 20 to be King/Queen of the park, but even with my boost turned to maximum on my Turbo Production, it would take me at least a week. I'd rather use the money to move 31 dragons to level 15.
It's a matter of priorities I guess, but those numbers are so huge that only a certain type of player seems to relate to them.

. With such lofty goals, I think the game developer might be experiencing unexpected consequences.
Just my two cents. I'll stay blue collar and keep grinding.
Poppy