No it isn't and to my knowledge it never was. My previous cto seemed to believe this too but dealing with greater throughput can be handled in several ways and

No it isn't and to my knowledge it never was. My previous cto seemed to believe this too but dealing with greater throughput can be handled in several ways and the first would be scaling your infrastructure. If you're using aws you can do this easily with elastic beanstalk, a load balancer and some triggers so that the system knows to create a new ec2 instance. The thing is tho your application would have to be built in such a way to support this. The more stateless your backend service the better for this and that usually comes down to session management. If you're using jwt and your backend doesn't keep any sessions your probs good. If your backend is keeping sessions then you need that centralized otherwise you'll have multiple instances using different session information and if your load balancer is directing traffic to instances on a round Robin or bases on based on throughput or something you'll end up with some confusing results on your client device. So you have to do extra work to make a monolith scale but micro services doesn't have to be that extra work. Much cheaper to spin up redis and have all your backend instances use redis for caching sessions, etc then it is to split your app in to micro services.