There is no other way though. I mean a bubble is when an industry is well established and delivers. Most companies in the crypto world are just getting their feet wet. Ethereum just went live last year and no major projects that engage with the general public have been delivered yet.
I can't see how we can have a bubble. I just can't. I think we have been living in the pit for so long that when we see regular folk entering, we got a little frightened and think this is a bubble.
I just can't see it. Not until at least half a trillion or something. My signal is one. My mom, who knows nothing about computers, starts talking about icos with her friend when they enjoy their morning coffee. When I sometimes say bitcoin and people around me have no idea what it is, then we are far, far away from a bubble.