I personally am not a huge fan of so-called "liquid" domains.
Unless:
1 - You can acquire them below the liquid price
2 - You can acquire them at the liquid price
*AND* there is an attribute that distinguishes it above the average.
Another important factor is that with lower cost liquid domains, medium and longer term holding fees can cut into your portfolio math. For example, 10 year holding costs (aka renewals) on $20k 3L.com acquisitions are insignificant at under 0.5%. However the same 10 year holding costs on a $100 4L.com is 100%.
IMO,
random 4L.com domains aren't great buys, and random 5L.com domains are terrible buys.
For 4L, and significantly more for 5L, the domains need to be strong, pronounceable, have implied meaning or be an acronym in an industry with money (helps a lot if it's also b2c).
So in the end that still leaves a small portion of 4L.com that are good buys .. but with 5L it's such a tiny fraction that to say 5L.com's are good is just wrong.
However .. yes .. 5L.com's that are easy to pronounce and spell, are strong phonetically or are the root of another word, are most certainly good buys. However, when you look at the numbers those are well under 1% of 5L combinations that are probably any good. There are 12 million 5L combinations .. of which the vast majority is worthless garbage like QYKJF.com or OUTTH.com
In the end companies get domains to people can find them .. which means memorability is a key factor. Most people just won't remember random 4L or 5L domains .. and there are even some 3L combinations which aren't particularly memorable.
I think people much more likely to remember a good meaningful 2 word combination than a 4L. But again, "meaningful 2 word combination" is also something which a very wide spectrum in terms of quality. With the big difference being that you can get them without paying a liquidity premium which put a huge dent in your profitability math.
That being said .. there most certainly are business owners who *think* 4L's are good/memorable .. and in the end that's all that counts .. so there still is potential in them .. but again .. make sure any 4L/5L you acquire has somehting special about them that translates into potential end user demand .. otherwise you're just playing a liquid market where your holding costs can really hurt you long term.
Also .. it's important to note that the Chinese domain market might as well be on another planet .. unless you know and understand that market, I think it's dangerous to venture there without some kind of strong inside knowledge. Seems to me the first Chinese bubble a few years ago turned out to be a lot of very bad investments (particularly 6N domains) combined with an unsustainable loan structure which eventually collapsed and caused the lower priced CHIPs to tumble in price as people needed to pay back their loans. Some would even compare what happened with Chips similar to a pyramid scheme. I personally think it was a combination of several things .. but I got into domaining just before the Chips peaked, and despite turning everywhere and everyone saying how hot they are, I avoided them like the plague because I just didn't see value in them because I just didn't see end users buying them in sustainable ratios.
All that said .. up to 3L and 4N .com's are still good domains and there will likely always be buyers for them (although I still would recommend against buying random ones blindly at liquid prices). I'm honestly not sure where 5N's fit .. but 6N's I'd avoid unless they are full of 8's .. lol.
In 2018 the $3.5 million sale of ICE was a big impact, while in 2017 we had ETH at $2.0 million and Fly at $2.89 million.
It's really important that new domainers do NOT confuse these sales with "random" or "liquid" 3L .com sales. All three of those have actual meaning that put them in a totally different class from 3L domains. Of them the only one that was sold as an acronym ironically was the actual word "ICE" .. but there's no doubt the buyer place a significant premium on the fact it was a real and VERY memorable dictionary word.