Genres are marketing terms. "If you like this game, you'll like this other game." They don't mean anything else because you cannot sensibly put Ultima 7 and Wizardry 7 in the same genre while also excluding Dragon Quest or Megami Tensei, except that the players of the prior games probably think that anime is gay
If that was true, you'd see more JRPG fans be interested in playing older CRPGs. Instead, I've seen numerous forum posts by JRPG fans (outside of this forum, obviously) saying something along the lines of "Mass Effect was the first western RPG I liked."
JRPGs obviously borrowed features from Ultima and Wizardry, but they're implemented in such a way that the similarities end up being mostly superficial. The top-down overworld in JRPGs was clearly inspired by Ultima, but unlike Ultima, most JRPGs are on rails with little room for exploration.
Most JRPGs have Wizardry-style combat, but this makes them less similar to CRPGs, not more. If there is a "default" style of combat in CRPGs, it's not Wizardry-style combat, but D&D-esque grid-based combat with individual character movement. And JRPG combat is only superficially similar to Wizardry anyway, with most of the variance and randomness stripped out.
...you have to remember that RPGs are about letting the player write their own story (or at least providing an illusion of that kind of collaborative storytelling).
This is a very vague and abstract way to define a genre. Dragon Quest 3 gives the player more choice than a game like Skyrim and that's barely even a matter of debate. Megami Tensei even has C&C with different joinable factions. There is absolutely no reason to put Shin Megami Tensei and Wizardry in two different genres besides "I think anime is gay", which is valid enough so you might as well just say that. And the claim that any of the Wizardry games were about "letting the player write their own story" is very dubious; Wizardry 1-5 at least are basically just mechanical obstacle courses like most old JRPGs
C&C as you seem to be defining it is not a CRPG thing. Having multiple "routes" and multiple endings is more of a JRPG/visual novel thing. CRPGs are not defined by C&C anyway, they are defined by certain mechanics and design decisions.
It's funny that you bring up Wizardry as a counter-argument. Even Wizardry, starting with 5, lets you pickpocket from NPCs, attack and kill them and converse with them through a text parser. All of these mechanics are virtually non-existent in JRPGs, with one or two exceptions, and even then it's just partial (Dark Souls lets you kill NPCs).
So obviously, CRPGs are mechanically distinct from JRPGs.