So I'd say it's probably even odds between some of them being around in the WC/SC custom map scene or some of them drawing inspiration from the same sources as those folks. Remember, the first Anno released in '98, AoE I in '97. I don't have much experience with Anno, but I damn sure do with AoE, and the whole tech-up and research process + increasingly high-tech building visuals reminds me very much of AoE, especially combined with the high-tension economic macro game.
Never played any of the anno series at all m'self, heh. Could see the visual aspect with AoE (though it was pretty common with custom junk, too, if generally with notably more limited models, ha), but the eco part (however high tension) is
way closer to how some of the custom map stuff did things than just about anything AoE's way. Infinite (but limited slots, so to speak) resource nodes were a vaguely common thing to do. Territory focused (risk style, etc.) ones moreso than freeform stuff, but it was a fairly general thing.
Add on the housing upgrade for money and pop thing in particular (
especially with the individual upgrading vs AoE's general age advancement), which was damn near ubiquitous, and, well... if it was arrived at without strong influence directly from the maps, they very much ended up making a buncha' the same decisions a good few other folks did a handful of years back. Which is totes possible by way of shared influences or whatev', it'd just make me a bit surprised.
Could you provide links?
Eh... not without a lot of very annoying digging (more than I have the will to do), tbh. There's a fair bucketload of the particular style of play, of very much varying quality and often identical or near identical names, heh, and while I directly played more than a few back in WC3 days (which is why the similarity hits me), it was never a major interest (and I kinda' sucked at it :V) so I don't remember much in the way of specific-enough-to-link examples. SC2 exposure's been more youtube vids, but it's been a good number of moons since that, too

There's almost certainly some on hive workshop or somethin', though. Civilization, world war, empire building, that'd probably be keywords that'd pull
something up.
But I don't get why there are parallels being drawn to WC or SC...
Least in my case it's specifically parallels with one of the sorta' more popular general styles of custom/player created maps that were made for 'em. Mechanics wise there's a good number of similarities with bits of design common to the general lot I've been mentioning. The base games for either have little to no resemblance, heh.
Graphics wise, the only thing that's
really hit me there is the first two available military units, as mentioned. The ranger and solider bear fairly notable (least to me) resemblance to the night elf archer and space marine models, respectively, and they were both common model choices for non-vanilla ranged units in WC3 custom maps. Marine was usually later on in tech trees, but not always.
... graphics wise, tbh, I think I might be most reminded of Heroes of Annihilated Empires, just... newer and more generally steampunk as opposed to a single faction. I have a sneaky suspicion that's more because I've just been watching vids and don't have free reign to zoom it or whatev', heh. It's in no small part just due to how the zombies clump up. The undead in HoAE could do stuff that looked pretty similar, if generally with fewer numbers... well, everyone did, but the undead specifically had zombies, too, so.