How many games of crazyhouse chess can be played in total compared to regular chess?

I'd just like to point out that for the largest number of possible games it's the 5 fold repletion rule that would apply and not the 3 fold repetition rule. Most chess players don't even know the difference.

Thank you for pointing this out. I guess that this rule is rarely needed in games with both players wanting to win, because the one with the weaker position would usually claim a draw. However in this case, we would need two players wanting the game to take as long as possible. So you are right according to FIDE rules.
On the other hand, i asked myself if this holds true for non-standard games: I tried it on the analysis board for 42 moves. in this case there are 4 positions and each of them happensto be repeated at least 10 times. this would indicate that the longest game that can be played on the analysis board is endless or at least only limited by the amount of memory available to actually do it.

For the analysis board: see this PGN (copy it into the analysis board mif you like):

[Variant "Crazyhouse"]

1. Nf3 Nf6 2. Ng1 Ng8 3. Nf3 Nf6 4. Ng1 Ng8 5. Nf3 Nf6 6. Ng1 Ng8 7. Nf3 Nf6 8. Ng1 Ng8 9. Nf3 Nf6 10. Ng1 Ng8 11. Nf3 Nf6 12. Ng1 Ng8 13. Nf3 Nf6 14. Ng1 Ng8 15. Nf3 Nf6 16. Ng1 Ng8 17. Nf3 Nf6 18. Ng1 Ng8 19. Nf3 Nf6 20. Ng1 Ng8 21. Nf3 Nf6 22. Ng1 Ng8 23. Nf3 Nf6 24. Ng1 Ng8 25. Nf3 Nf6 26. Ng1 Ng8 27. Nf3 Nf6 28. Ng1 Ng8 29. Nf3 Nf6 30. Ng1 Ng8 31. Nf3 Nf6 32. Ng1 Ng8 33. Nf3 Nf6 34. Ng1 Ng8 35. Nf3 Nf6 36. Ng1 Ng8 37. Nf3 Nf6 38. Ng1 Ng8 39. Nf3 Nf6 40. Ng1 Ng8 41. Nf3 Nf6 42. Ng1 Ng8