Scarcity is one of the reasons why bitcoin keeps increasing because there are so many investors who are willing to buy bitcoin at any given price because of its scarcity, which triggers the price to increase.
Snipsome people are still feeling that Bitcoin is expensive at it current price, however that's not true the fact is that we as humans are always scared of taking the right steps, when Bitcoin was $30k some set of people still saw it as being very expensive and that made them to invest in shitcoins however in just few months and years Bitcoin has doubled in value and those shitcoins they invited there money to has remain stagnant some has even went below there initial price value.
Those that are into Long term Bitcoin investment won't have this thought that Bitcoin is too expensive, it is only those who are traders that always have such feelings because they feel if they buy at high price they will lose, if anyone feels Bitcoin is too expensive now and because of that he won't start accumulation let him or her get ready to regret because surely Bitcoin will double in it's price value because Bitcoin has not grown to half of it's limit.
And yeah it is true that Bitcoin is highly volatile in nature however it's volatility doesn't negatively affects your investment as a Long term hodler, the significant gap between its current price and its potential future value prevents Bitcoin's volatility from having a major impact over the long term hodlers, if you keep focusing on the current price of Bitcoin and think is too expensive then you will regret will the price double in future.
Accumulate little by little now that the opportunity is here because the future of Bitcoin is very bright.
Dude to be honest with you the price of Bitcoin now is really expensive even though it hasn't gotten to half of it's future value but currently now it is expensive and the people that sees it to be more and very expensive are people who don't understand the benefit of investing and holding, and some think they can't buy little by little because they don't have an idea.
However, traders doesn't actually look at the price of Bitcoin or how expensive it is all they do is look at the market, carry out there analysis and suggest the possible result or the possible movement of the market. In as much as our income are not the same hence Bitcoin will continue to be expensive to some individual and not only to some individual but also to some investors.
Of course traders time the market on when to buy and sell to make profit and that has nothing to do with investor. And who is talking about traders here? I don't see how those two sentences correlate or conjugate. I just feel like flogging you right now if I where your teacher in high school college, sounds like you are a little bit tipsy on whisky 
Believe me that what we seeing now as too expensive in the price of Bitcoin cannot be compare to the value of Bitcoin in the future because it's very certain that the price will skyrocket in the future. So a good investor don't look at the high price of a commodity but the economic potential and sustainability of the commodity in regard to the possibility of bringing a profitable return on the investment in the near future which a believe that Bitcoin is that unique commodity.
The quest for Bitcoin investment will always have positive increase in the future which will in turn result to increase in price, so for this reason I think it's advisable for every investor have the financial capacity to aquire Bitcoin to accumulate more Bitcoin as much as possible now and hold it for a long time because those that will preserver to hold it for long time will surely have a good rate of return in the near future because Bitcoin will surely be the most source after commodity in the world in the near future.