given the importance placed on family lineage in their culture
Just out of curiosity, what importance?
In the two Vulcan families we followed up close, Spock's and T'Pol's, estrangement was the word of the day. Tuvok's family tried to remain close-knit across the galaxy, but there was never any stuff on grandparents or ancestors, nor mention of family traditions.
Spock's folks had ancestral ceremonial grounds, but how is that a "lineage" thing? Apparently they cross-married on those grounds regardless of lineages, sometimes even with alien animal women from outer space.
Put short, I don't get an impression of "ancestor worship" or even "lineage respect" in the canonical or even the common novelized appearances of Vulcans. These logical and superstition-free folks tend to be self-made men and women to a large degree, and they actually view tradition with embarrassment and disdain... And I don't think any one of them has ever
spoken highly of a preceding generation. Surak worship is something universal to the modern Vulcan, not something specific to Spock's bloodline.
Are we talking about the same Vulcans? Seriously, Vulcans place great importance on their long-standing traditions and their ancestors. This has been evident both on TV and in the modern novel continuity for some time. Superstition and tradition, by the way, are not the same thing. Katra
belief is not superstition as katras
are real, and consulting the katras
of the dead, even carrying them around within one, is seemingly reasonably common. 22nd century High Command may have been opposed to it, but they were a rather intolerant regime.
Anyway, remember that Vulcans who spend their lives among humans and other species are somewhat unusual anyway. Vulcans, their position as a lead member of the Federation notwithstanding, have always been somewhat insular as a people, when it comes to their private cultural traditions. Even T'pau, in "Amok Time" behaved that way, and she has very good relations with humans and other outworlders, as seen in "Enterprise".
As for Spock, remember one of the major reasons for the estrangement from Sarek was his decision to join the Starfleet rather than follow tradition and enrol at the prestigious Vulcan Science Academy. And while Sarek may have married a human, he certainly seemed to expect their son to be Vulcan, not human, in behaviour, didn't he?
Yes, Surak is held in the highest of regard by all Vulcans. My point was not to suggest otherwise, but to say that, since the novels say Spock's family is an offshoot of his clan, maybe only members of this extended family make a point of taking names similiar to his. Perhaps that is their privilige.