Note that I'm not saying "easier" or "harder". It is different, though.
This is a real difference, and one I want to expand on in my next article. You can fuck around much more in a web context than embedded, but you still often find out.
Doing web "well" requires thinking in terms of realtime and memory constraints. I don't want the latency of my microservice to jitter, nor do I want it to use random amounts of memory. Not only will I be able to provision smaller machines, but I will also guarantee better SLAs. Building your microservice just like you would a hard realtime constraint (guaranteed memory usage per request, preferably no allocations at all, time guarantees (response within 50 ms or I fail) helps make a robust, performant and resilient web application.
The real-time aspect and hard resource constraint are indeed the fundamental difference. Some of these (static memory allocation) make a lot of sense when building microservices, for example, but it's much more squishy. I personally like building my microservices very similarly to my embedded systems: event driven, with different priorities to ensure time constraints, and bounded statically allocated memory and queues. Even in languages like golang, my allocations are usually done up front, memory ownership is very clearly delineated.
While you might not have realtime in web systems, you very much want to avoid GC pauses and similar behaviour to avoid spiking your latency, as these things compound. The underlying concepts are a bit similar, at least in my head. I think "this needs to be O(1) in runtime and memory to be repeatable. If the constant factor is bad, we can work on that. But I don't need fast and elastic).
As for distributed system, I actually consider a SPI / i2c / CAN system to be the distributed system, and a lot of patterns (retry mailboxes, timeouts, promises, bounded queues, circuit breaker) make sense in both.
I definitely plan to write more about these lower level details, and provide some code examples to make the parallels more evident.