bitcoin is five years time in my opinion there will be a lot of hard forks from the original bitcoin blockchain
there already has been hundreds if not more, forks of bitcoin! what do you think litecoin, dogecoin, namecoin,.... are? there has been a lot which even used bitcoin name and blockchain! like bitcore (BTX) which even has SegWit on it!
and the value of bitcoin would increase by 300 percent today's price.
i think you made some calculation errors.
each year price has gone up at least 150% and this year alone, since the adoption got a big boom, the price rose >250%
and just like any other new booming and adopting technology this percentage will only increase each year.
in other words your 300% will be for 1 year, probably even less. but not at all 5 years!!
if transaction's speed and price remains the same, bitcoin's not improving and maybe the price wont grow that much
transactions are instant. they take at most 5 seconds to propagate throughout the whole decentralized bitcoin network.
the blocks, by design, will be found on average 10 minutes and that is your confirmation time.
that is the design of bitcoin. others tried changing that and have failed so far. that leaves bitcoin without opponent and growing. so far this growth has only increased and will continue to do so. and with more adoption, higher price follows.