Why has everything become short-form video?

Because short vertical video outperformed everything else on the metrics platforms optimise for, and once one platform proved it, the rest had no commercial choice but to follow.

What made the format so effective:

A vastly faster feedback loop. A recommendation system learns from outcomes. With short videos, a user delivers a clear signal — watched to the end, rewatched, skipped after two seconds — every few seconds rather than every few minutes. That is orders of magnitude more training data per user per session, so the recommender gets accurate about your taste extraordinarily quickly.

Recommendation over subscription. TikTok's central innovation was surfacing content from accounts you do not follow, ranked purely on predicted interest. This decoupled reach from follower count, meaning any video could go viral — which attracted creators — and meant the feed never ran out.

Low production cost. A phone is sufficient. Supply is effectively unlimited.

High completion rates. Short content is finished, and completion is a strong positive signal, so the format flatters the metrics by construction.

Why every platform copied it. Time spent is the currency for advertising revenue. When a competitor demonstrably captures more of it, matching is defensive. Reels, Shorts and their equivalents were launched as direct responses, and existing platforms had the distribution to make them work.

What is being traded away: discovery favours immediacy over depth, subscriptions and follower relationships matter less, and long-form work is harder to sustain. Several platforms have subsequently pushed longer short-form — minutes rather than seconds — partly to capture advertising formats that need more runtime.

Creator economics are difficult. Enormous view counts often convert to modest revenue, and reach is unstable because it depends on recommendation rather than an audience you own.