Your market share estimates for the Google and TradeDesk DSPs are very close to an estimate published by the Wall Street Journal on 3/4/21 (in an article titled "Google Crushed Many Digital Ad Rivals. But a Challenger Is Rising."). You estimated 42% and 8% respectively, and they estimated 40% and 8%. So this helps to support that your estimates are in the right ballpark.
Your market share estimates for the Google and TradeDesk DSPs are very close to an estimate published by the Wall Street Journal on 3/4/21 (in an article titled "Google Crushed Many Digital Ad Rivals. But a Challenger Is Rising."). You estimated 42% and 8% respectively, and they estimated 40% and 8%. So this helps to support that your estimates are in the right ballpark.