I’ve wrestled with the weight weenie thing for years and eventually learned that some things are worth the weight. 
For instance, tires. Slicks are nice & light but obviously have drawbacks. That model applies to most moving parts on the bike IMO.
If I were building a bike today here are choices on the stuff I think matters:
Tires – WTB Mutano 2.4 (about 700g, very fat profile with good tread, rolls fast)
Stan’s notubes with yellow tape, no rimstrip
Wheels – Stan’s or American Classic 350g rims, 32 spoke, AL nipples, hubs not so important
Seatpost – any of the "dropper" posts, this adds weight but I ride noticeably faster with it
(I’ve used those Ritchey WCS tires you mentioned, they’re light & fast for sure but very thin. Mine wore out quickly & had lots of flats in the second part of their life)
Some things that are nice for visual appeal or mental lite-ness –
Cranks, Cassettes with nice machining or Ti, Ti pedal axles, 2×9/10 gearing, sweet hubs
But none of the above things have any real impact on riding performance. IMO anyway.
Easy places to save weight but don’t make you faster –
QR skewers, bars & stem, seat, grips