The .com advantage
A strong .com can combine universal recognition, broad buyer compatibility and comparatively deep investor liquidity. That does not rescue weak wording, long constructions or low commercial relevance.
Use extension-specific evidence
Because .com is the default commercial extension in many markets, comparable sales are usually more plentiful than for smaller TLDs. Compare like with like: one-word generics should not be benchmarked against long descriptive phrases simply because both end in .com.
Run the domain through the same framework
Extension quality is one factor among naming power, clarity, commercial intent, scarcity, build potential, liquidity and buyer depth.