You're mixing up voting shares and Class A common stock
Class A shares (such as TCI have) have regular voting rights. Class B shares (such as Larry and Sergey have) have 10x voting rights. Thus, as I understand it, TCI's voting voting power is at most roughly ~0.5. In practice, it's way less than that due to all the class B shares[0], reinforcing my point.
[0] https://capital.com/alphabet-shareholder-who-owns-most-googl
>GuruFocus data, as of 29 November 2022, revealed that 59.13% of Alphabet’s stock was owned by insiders, including the two founders, while 22.21% of common shares were owned by institutions including brokerage firms, hedge funds, pension funds and asset management companies.
Ownership percentage is only important because of how it lets them impact the stock price.