Bitcoin was expected to replace money in fiat transactions, though, time passes, and bitcoin, as well as other cryptocurrencies, are used rather as a value store than for any other purposes.
Why investors are reluctant to spend their crypto-coins?
This is happening because of several reasons. First of all, most of them still believe that their cryptomoney will grow, hence, they want to get as much as possible from their investments.
Though there is a possibility as well, that cryptocurrencies will grow immensely and then suddenly simply stop existing. They are backed up just with our trust, other than that they are just protocols backed up by nothing.
Second, and this is especially valid for a bitcoin, it is very inconvenient selling bitcoins, as there is no reliable infrastructure for that.
And third, and the last reason is that selling cryptocurrency costs. Every exchange has its own fee, but the fee exists and it is not so low.