They could employ a bunch of people whose job would be to go to https://bridges.torproject.org/ request bridges, solve captchas and add bridges to the block list and request bridges over gmail.
I asked this question before and the answer was something along the lines that there is a limit of how much and what bridges are given to users based on their IP address and geolocation but that is not the answer because they could give this people totally uncensored access to the internet so that they can use VPNs and Tor itself to circumvent this limitation.