At my job, we’ve been using observables in our React front-ends for at least the last three years. These are high traffic consumer websites. We’ve had great success with them and haven’t experienced any of the issues you describe.
I guess the key is to minimise the amount of code that directly subscribes, don’t mutate data as it flows through an observable, and where possible, prefer deriving one observable from another over using imperative code to push data from one observable into another.
In React you can use higher order components and whatnot to handle subscriptions, and that capability most unfortunately is not available on all frameworks. Perhaps most egregiously, Angular doesn't really have any concept that works in place of HoCs, though at least you can sometimes fold observables using the async pipe.
I guess the key is to minimise the amount of code that directly subscribes, don’t mutate data as it flows through an observable, and where possible, prefer deriving one observable from another over using imperative code to push data from one observable into another.