"Fear" might be a strong word perhaps. "Annoyance" is probably more accurate (for me anyway). I do enjoy watching some Youtubers who upload retro computing videos, but it is hard to ignore the very real effect they have on increasing the rate at which prices rise.
One such example off the top of my head was about 18-20 months ago when I bought a Unisys CWD4001 off eBay for $75 USD. The seller had probably at least a hundred for sale IIRC. I remember checking the sold history on that auction and noticed that they had only been selling in dribs and drabs over the past 6 months. Anyway, coincidentally about a month or so later, LGR put out a video on these machines. The day after watching this video myself, I checked the eBay auction I had bought mine from again and saw that many had sold on the same day that LGR had put out that video. The seller had doubled the price in reaction to this (If I'm being honest, I cannot say that I blame him). That auction still eventually sold out completely with that doubled price... I think he had even increased it a little bit more a couple weeks later.
This is just how it goes of course. Prices are going to rise inevitably anyway as these things break down, get thrown out, etc. and the available stock dwindles. But, I think it's fairly safe to say that Youtubers do have a direct impact on price.