First off, just wanted to say thanks for submitting this feature request. Internally, we have dubbed this feature 'shared assets', as it essentially would allow you to build an asset (such as a group of images, or a page section) and call that in on numerous different pages. If you were to make a change to the original asset, the changes would reflect across all pages this was used on.
I had a long chat with Paul from our product team about this functionality, and where it is on our radar. While we don't have an exact date for this feature, we're hoping to tackle this later this year, if all of our scheduled features are released without issue.
While we don't really have a way to do this in app right now, I was able to craft a little workaround that should work for what you're looking to do now.
Take a look at this published page:
You'll notice this is only a single page section and nothing more. This would serve as my 'master' template, which I'll then call in on this page, and this page. If I publish any changes to my 'master' page section, they will update across all pages that it's published on.
Basically, I'm just creating my 'master' page section separately, then placing it on my other two pages by using a bit of custom code in an iframe. By doing it this way, you can create different pieces of content, or entire page sections, and call them in across hundreds of different pages. Then, if you want to make changes to that asset, then you only need to do it once and it will reflect across all pages it's published to. This could be especially useful for building things such as footers, or nav bars (which by the way are really not recommended on landing pages).
If this is something you'd be interested in trying, let me know and I'll whip up a little tutorial and give you the best iframe code to use.