The deflation rate has been about 50% for the last couple of years with bitcoin, but you're right it'll be in the teens or something in the future, still horrible.
This is it's flaw by design and the reason I never invested. This is the same reason we don't use gold anymore, even though it's supply is still growing, but less than that of GDP growth. Any deflation, even a few percent, is unwanted in your money because it promotes hoarding and discourages lending.
There's a reason why the billionaires promote the gold standard, it's so they can just stockpile gold and not bother investing. Any money used today grows exponentially, to match or outpace the growth of GDP. This is the entire point of money, it's not meant to be an investment, that just hurts the rest of the economy.
Your iphone analogy is pointless, it has nothing at all to do with investment in new companies or the stickiness of wages, it's just a talking point made by gold advocates. The point of deflation being bad is that banks would just save your money, instead of loaning it out. If it was bitcoins with a 10% deflation rate, they'd have to make a 10% return just to break even. You're confusing personal finances with money in large markets, and you sound like every other gold advocate that's been bought and paid for.