Nope. Never did I say or imply "number of lines".
But let's talk about the number of lines then. It looks like "boring languages" are quite happy without monads even though "once you're working on a larger codebase, being able to support new effects... and being able to generalise... is much more important." Seems to me, this statement must be supported by data.
Meanwhile let's talk about large projects. You know, the Hadoops, and the Cassandras, and the Kafkas, and the ActiveMQs, and the Tinkerpops, and the Mesoses, and the Nettys, and the Kuberneteses, and the Dockers, and the <insert dozens of other names here> of this world.
They are all developed and have taken over the world without monads at language level. Either they are small projects (they aren't) or the need to shove monads everywhere is highly exaggerated. Because I've yet to see an abundance of projects of the same calibre from the Haskell (and friends) world.
Kafka is written in Scala. That aside, I'm not convinced those are such large projects. How much logic do they need? People build large projects on top of them - I've done so - but where's the complexity in the components themselves?
What is a large project then?
Apparently, a distributed database isn't it. A distributed data processing framework isn't it. A high-performance web server isn't it. Nothing in the list is it.
What is "a large project"? Especially one, where monads are so important?
So far I only got "I think", "I work on a project", "I'm not convinced" and "I built a project on top of these". Hardly an argument, is it?
Well, boring languages will always win if you're counting lines, because they use a lot more lines to do the same thing. I work on a large Scala project and have worked on others before; these are real projects that produce a lot of business value, and would have been a lot more difficult or even impossible without those language features.