Kind've yes, but people that bought .com early on had to pay a lot to register them, it was a big risk. XYZ names were worthless, seen as a spam extension and available for 99 cents a name, that's the point that most of these names were snapped up, they were dropped again and then picked up for cheap again, leaving the large portfolio we see today - obviously there has been reinvestment since, like the bull domain that you speak about.
Unfortunately we don't get the full picture when we see these sales, in order to make good investment decisions we must see the full picture. One person coming out and saying they sold one random name for $$$$$$$$$$$$ or one person owning nearly all of the good non-prem names and having a great sell through rate isn't necessarily good enough of a reason to invest - everyone should look at the full picture and decide what they are willing to lose in order to gain.
The truth is there has been a risk, but it was at 99 cents a pop and then XYZ became a known extension amongst a niche that has deep pockets - the stars aligned in a big way in order for this success to happen and more power to the owner/seller - but in my opinion with XYZ it is nigh-on impossible to replicate and that's OK with me. I'm glad that someone is reaping the rewards even that person is saltier than the dead sea
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There is no way to know what will sell in .xyz, they are usually obscure words and if they are premium renewals you can pretty much forget it and leave it to the registry to pick up those gains. For instance, it wouldn't be worth it for me to invest in a .xyz name for 10k as a gamble, it would either be a non-prem domain that has too large a chance of not selling or a premium domain that might sell because it's a traditionally decent keyword but the renewal would make a bad proposition as an investment.
I had a chance with stream.xyz, that was available for the taking and I didn't take it... as I would almost certainly lose my money (that's a premium renewal). It was snapped up minutes after I made that post... good luck to the owner. XYZ success is just not something that can be replicated NOW with the current conditions in my humble opinion.
Again, congrats to the seller of this name, and the others that have sold, cause it's really good! Awesome in-fact and I don't want to take that away from them. It doesn't really matter how much luck it took, cause as you say it's all luck too some degree - but if you take the intelligence out of investing in domains completely then what's the point in being on this forum discussing domains? That's why I get fed up of downvoters that don't think.