In my opinion this will be a good thing as so much of the economic "growth" we see in the world today is a vacuous re-packaging of frivolous fancies to meet imaginary needs fueled by an incentive to spend currency that is always losing value. Things that satisfy a genuine pressing need will continue to be invented, bought and sold and this is all that is necessary for a vibrant healthy economy.
As much as I might want to agree that all that you have said does make a lot of sense, it's still important you understand that the acceptance of bitcoin into the mainstream financial market won't in any way shrink the economy of any country, expect for countries who's economy has or had been previously bad.
Bitcoin is another form of money, and there is no way (not even in the next 30 or 40 years) that Bitcoin will completely wipe out fiat, both will co-exist in harmony, and this is because, people are still going to be needing fiat to invest in bitcoin, which is a means through which bitcoin will become more valuable, and those that live in rural areas where internet is a big problem; are always going to need fiat for their day to day buying and selling transactions.
Every economy will go on as normally, the only thing I see is that alot alot of people are definitely going to be pumping alot of fiat into bitcoin, which may cause the central banks to print even more.