Selling BTC now or sometime in the future is not same thing for everybody,people invest money in BTC when is worth less then 1$,and they invest when was worth 20 000$.For the one who invested a relatively small amount of money 11400$ or 12000$ does not represent a big difference,for others who invest at higher price then it is today, really does not make sense to sell at todays price and lose investment.
Anyone who owns BTC today should be kept in mind that value of 1 BTC has tremendous potential in the future regarding price.Also BTC as currency should be on track again with SegWit and LN,so why convert in fiat if you have another choice.
This is the greatly important thing to remember when considering why people are selling, everyone's circumstances are different in terms of financial commitments etc and then there is also the consideration of what point they entered in to the market. For someone who entered at $1k for example, a price difference from $11k to $12k isn't such a big difference for them, they are either 1000% up or 1100% up. Whereas then for someone who invested at say 10k, then a much larger amount of their profit is on the table. This is all in real terms, in percentage terms it is all relative but given that for most people the fiat value of their investment has some value, we often do not think in purely relative terms.
For anyone looking to invest right now I think the important thing is to consider those things that you have mentioned, you should not be looking to make a quick 4/5% on 11.5k to 12k and instead be looking to invest for the future and a much bigger return, we will most probably see a new ATH at some point in 2018 and that would be a 100% profit or more for anyone investing now, when the changes you mentioned come in to play then bitcoin can again be suited to being used as a payment option, assuming they fix the current high fee problem.
