The evidence strongly supports the statement that trading volumes on perpetual DEXs have decreased leading up to a mainnet launch, primarily due to the dynamics of airdrop farming incentives.Several high-authority and highly relevant sources corroborate the underlying mechanism. A report from The Block explains that trading volumes are heavily influenced by incentive cycles like airdrop farming. The official account for Hyperliquid, a perpetual DEX, discusses how trading volume can be manipulated for airdrops. This establishes a common pattern where users generate high trading volume to qualify for a token airdrop, an activity that typically concludes with a 'snapshot' taken just before the mainnet or token launch. Once the incentive to farm the airdrop is removed, this artificial volume disappears, leading to a sharp decrease.A highly credible research profile from Messari on MYX Finance provides a direct, specific example of this phenomenon, noting that trading volume 'declined sharply' in the context of perpetuals and airdrop farming.While there is some conflicting information, it is less specific and carries less weight. A post from VOOI, a DEX aggregator, mentions a 'surge' in volume, but this lacks the context of whether it was for a specific DEX leading up to its own launch. A news feed from Phemex reports 'mixed results' for perpetual DEX volumes, which acknowledges that declines are occurring, even if the trend isn't universal. This does not fundamentally contradict the statement but suggests it is a common pattern rather than an absolute rule.Overall, the most authoritative and relevant sources provide a clear mechanism (the end of airdrop incentives) and a specific example (MYX Finance) that directly support the statement, making it highly likely to be true.