Re: Will the need to increase BTC's max supply arise in the future?
The question then is how much of a block reward is necessary to prevent a 51% attack, and will fees be enough? The answer to that question is unknown. We have seen 51% attacks against other coins, so we know how much is not enough. We just don't know how much is enough.
any POW coin that shares mining algorithms (eg SHA256) and has a weaker hash rate is vulnerable to a 51% attack. every SHA256 coin is extremely vulnerable to attack by bitcoin miners. this is one of the reasons why minority hard forks are not particularly viable---minority miners must live in constant fear of rollbacks by majority miners.
unfortunately, that doesn't tell us much about the hash rate required to keep bitcoin secure from 51% attacks.
Do you think that the need to increase BTC's max supply will arise in the future? Or will Bitcoin be able to "live" just fine with a max supply of 21 million coins? Your input will be greatly appreciated. 
No. There is no benefit to increasing the limit.what is your reaction to this assertion made by peter todd? https://twitter.com/peterktodd/status/697532042553065472
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IMO Bitcoin should have had an explicit 1%/year or so security tax, implemented via inflation.