I see One more reason for the breakage...

The Bitcoin Mining today has become a bigger challenge as teh difficulty in mining is increasing. Now if the difficulty is increased by one more zero in Block chain hash, then the amount of energy consumed to generate the block becomes expensive than the earning. So since it becomes not profitable for miners and only hard work and capital expense, if the Miners stop, then the Blocks added to chain will stop.. Also there may be other reasons like, Global warming, Carbon footprints may be raised after a while, which may lead to decline.,..
If to sideline this, they start making the challenges of Mining simple, then Miners will generate huge money and this may inturn make BTC to lose value.. SO next level of difficulty must be harder than the present level or may be as Hard as this level.. That may be done by adding 1 in place of 0... Now how will it be done is the question... But Global warming is the question which will not be answered, as the mining machines drink up HIgh amount of Power and decepate it as Heat into the atmosphere... This can be dangerous... Unless a new system(Other than HASHING) is found for Bitcoin Blockchain Ledger, this global warming mechanism may derail the whole process..