Factor 1 — Incumbent authority accumulation (the deepest moat)

Claim: The slowest moat to close — referring domains + brand search demand + content history. Domain AGE itself not a ranking factor (Mueller 2019 — "domain age helps nothing") — older domains win via accumulated signals.

Sub-evidence:

• 66.31% of all web pages have ZERO backlinks (Ahrefs, ~1B pages analyzed). ~94% get no Google search traffic. Incumbents with diversified link profiles sit in a small, hard-to-join club. See Ahrefs — 66.31% of web pages have ZERO backlinks; ~94% get no Google traffic (vendor).
• 72.9% of pages in Google's top 10 are more than three years old; average #1 page is 5 years old (Ahrefs). Corroborated by SE Ranking — majority of top-10 domains 15+ years old. See Ahrefs — average #1 ranking page is 5 years old; 72.9% of top 10 is 3+ years.
• NavBoost — confirmed under oath by Google VP Pandu Nayak in DOJ v. Google 2023. Click-based re-ranking system with 13-month rolling window; entrenches incumbents via accumulated "good clicks." See NavBoost — Google's 13-month click-based re-ranking, confirmed under oath in DOJ v. Google 2023.
• Brand / branded search demand is increasingly important and hard to fake. Google rolled out a Branded Queries filter in Search Console in late 2025, signaling investment in measuring brand entities.

Timeframe to close the gap: 4-12 months meaningful traction; longer for competitive terms. New domains commonly take 6-12+ months in competitive niches.

Honest concession: Incumbency is not destiny. Adilo's 2,000-keyword analysis (independent / non-vendor) found 66% of cases where a lower-DA site outranked higher-DA competitors, and >30% where a site 10+ DA points lower ranked #1 — driven by superior intent match, page-level relevance, engagement. Authority gaps ARE surmountable on narrow, well-matched, lower-competition queries — NOT on head terms.