(*) it is obvious because bitcoin is not a good unit of account, there's no mechanism in it that adapts the emission of bitcoin with its value with the aim to stabilize it, and bitcoiners are even proud of that. Something that is not a good unit of account (volatile value) cannot be generally used as a currency in a payment system.
Bitcoin has perfect stability - it has always maintained a value of 1BTC = 1BTC.
Oh, you meant its price in USD? Why would that be relevant to its stability? You are using a very unstable currency (USD) as a measuring stick. Any currency that replaces fiat must be volatile, because it has a lot of growing to get to that point, and its not going to chart a straight line on the way.
8MB right now is not safe, it's too much, nodes will drop likes flies. Im dumping my node for sure at 8MB.
Are you talking to us from 2005? 1MB, 8MB, 32MB...these are all insignificant amounts in today's world. To argue otherwise just ruins any credibility you may have had.