Once more. Dollar is perceived as stable, but slowly depreciates at 1.5% to5% per year. That is maybe stable day to day, but it is not at all stable over a decennium.
Bitcoin is designed to be stable over decennia, but is currently not stable day to day. There is a risk of 10 % down at any day, but after 10 years it is either stable or going up. So it is stable over some longer period, but it is volatile day to day. So, it you can stomach the day to day risk, it is stable over 10 years or even 3 years. Better than that for savers, it is expected to go up, even if there is a day to day risk.
Your logic is rather perverted and lacks grounding at all. Bitcoin doesn't have 10 years behind it to give you any viable reasons for saying that "after 10 years it is either stable or going up". There is just nothing to base your argument upon so far.