We quite often discuss similar topic on Russian forums. And it usually comes to the moment when someone reminds the concept of 3 knives: one knife for cutting, one knife as a multi-tool and one knife for chopping and other hard work. This division was made because carving and cutting jobs usually require short and light blades while chopping requires long and heavy. If you combine carving and chopping in one knife, it will be a poor performer. You can combine multi-tool and cutting knife, but you will have to wash it too often for comfort, so again it is not the optimal solution. So, on the question if you should carry a few blades (knives), yes, I think it is a good solution.
If you are concerned about blade length, well, then you can substitute long blade by an axe or saw for heavy work. But they are good as long as you don't need to cut through bushes.
Regards,