To say one has no need to withdraw it into a hard currency is pointless and illogical.
Why? What would be so desirable about exchanging into another form of currency when you consider a single BTC reaching $1 million; extraordinarily high demand, there would likely be very few, if any, goods or services that couldn't be paid with BTC by that time. You are correct in that right now, the tangible items that can easily be bought with BTC are limited, but they are growing daily. Food, Clothing, Electronics, Autos, Media & Entertainment, Professional Services, even Real Estate can all be bought with BTC right now.
My guess is no, most are in it for the run up and get out quick before it ends, make a few bucks etc...
I can't say that I disagree with this; you may very well be right. I don't think there is any doubt that the largest majority of BTC holders at the moment are entirely speculative. What I don't think is fair to assume, is that being the case in 5, 10+ years. If in even a couple years, the landscape hasn't changed from speculators to consumers, the opportunity for BTC will likely have passed and it will be game over.
That isn't too mention the fact of how many others would be in the same withdrawal conundrum boat with Billions or possibly Trillions of dollars in BTC
Again, this is with the assumption that people will actually want to exchange into the state currency. It isn't hard to imagine a very poor outlook for fiat money in the future when we can already see the state of disrepair it has become for many countries; and that our current methods of supporting our respective domestic economies are not producing desirable results. We are a global marketplace, and BTC is built perfectly well for that, without, and this is important, diminishing any benefits for small, local business. The largest uptake by merchants now are with small businesses, and it is only a matter of clarifying legislative gray area before the big fish decide it is time to jump in the pool. It will be the great benefits to the merchant<>consumer relationship that BTC, possibly another crypto, will eventually be the preferred currency of exchange.
To be fully honest about it, I don't expect BTC will reach the kinda of outlandish estimates of $100k - $1 million per coin, certainly not in less than 10 years. I also don't expect it will create as many billionaires and millionaires as everyone hopes for, but it will make many people very wealthy.