The previous ATH for ETH was at the bottom of the Bitcoin growth curve. Let's guess, hypothetically, that the next Bitcoin ATH were on Oct 18th, again, there's no validation to my statement; and, if, ETH were to peak, again at the bottom of the growth curve, that would take us to 23k.
Let's also view this from another point ontop of the chart shown -- right now, BTC is at a price where retail purchases are nearly impossible for the majority. What's the number 2 coin? ETH. If folks were to flood into ETH as much as they did for BTC during 2017 fomo and current 2020 pump; that could easily take us pretty high.
Again, take this with a bit of salt; this is not a TA; it's just an idea.