If I was 100% sure that this year BTC will be worth 100k, I would invest all my money and take out a loan ... But life is not so easy;) we can only hope that it will happen 
Nobody in this space is 100% sure that it will rise to that extent during this year only. Yes you can have some sort of realistic prediction but having a 5 year target would also be very long time in virtual currency as many things depend upon different government or the lawmakers of the world. Infact you should be buying now because market in coming time will rise and you can make money through this rise .