The safe, tried-and-true way to build typical web crap is to stick the one, blessed database in the middle, and then dangle all the dependencies off that. Everything is synchronous because it's simpler, and it's what the seniors grew up with.
And then one day you won't be able to run your new history feature, because it's locking up the database for too long and new transactions are timing out.
The juniors only get to run the show and introduce exotic, non-boring technology (asynchronicity, event-sourcing, eventual consistency, CQRS etc.) after the seniors have admitted defeat.