I tried to list all the issue and PR about that subject, I wrote then down in following post:
Both following PR for webpack exists since a while but where never merged 
In his last Ionic blog post, @danbucholtz briefly spoke about the introduction of angular ngo, maybe not gonna solve this problem but should help to improve the major effect of not using lazy loading, respectively increase the boot time
When it comes to me I decided a while ago to not use yet lazy loading even if my app has quite a size (something like > 30 pages, > 40 components) … maybe I should give another try with one module pro component and see how my boot time improve and how the size of the app goes bigger…