Keep in mind that makers are there to earn fees. Any privacy achieved by them is a side effect, it isn't the goal of their participation. Significant changes would have to be made to enforce their privacy. For example, blind signatures wouldn't help if the taker can select only one maker for the coinjoin, since the two outputs that don't belong to the taker belong to the maker. So the minimum number of makers in a transaction would have to be enforced.

Having the taker be the coordinator has its advantages. A user that needs to mix their coins can do so any time they want, with any schedule they want. They don't have to wait for enough participants to join or for the round to start. They can even pay someone through a coinjoin, since they choose the amount and destination of the transaction. With Wasabi or Whirlpool, you'd have to use an output from a former coinjoin for the payment, you couldn't start the coinjoin specifically to send the money.

See these issues by @Max Hillebrand:
https://github.com/JoinMarket-Org/joinmarket-clientserver/issues/1192
https://github.com/JoinMarket-Org/joinmarket-clientserver/issues/583