If Bitcoin becomes widespread enough that most people hold their savings in it, then it will greatly and permanently reduce liquidity in the financial system, lead to a decrease in consumer spending and cause major ructions in the global economy.
I think this would not happen because no matter how many bitcoins are lost and how much are being saved by the whales, the value of each Satoshi will increase and there will be no dent in the consumer spending. Think of a society that have no fiat money and only Satoshi's / bitcoins/ do you think that people will stop spending the bitcoins and not meet their needs ?
I think as more and more adoption of Bitcoin grows, it will only help strengthen Bitcoin and reduce inflation. Also due to transparent blockchain, there will be no chances of corruption and no more easy money for the governments (who enjoy printing fiat currencies).