The world of pre-built themes has traditionally focused on an "all-in" model. That is to say, you get a theme; it does what it does; you use it as is, be happy.
What's that you say? You want it to do something else? Tweak it a little here and there? Whether that's going to be a solid experience or a slide into CMS layout hair-pulling-out anarchy is up in the air.
The power of pre-built all-in themes for CMSs are, not surprisingly, scale and budget. Find an audience that can consume these in huge numbers and make sure we're getting these themes out there as quickly and cheaply as possible. A website design super-assembly line if you will.
For the most part, they do achieve this well enough as far as mass-produced look and feel assembly lines go. Focus on constant flow of theme regurgitation, slap them out there in large numbers one by one. It's not about malleability, it's about a repeat theme-selling business model based on micro-instant-gratification theme by theme.
The technical and business thought processes seem logical enough, but it doesn't work out the way you might think much of the time. It's why, for completely opposite reasons, the layout management engine by Netgen has become such a powerful part of the iTMG toolset.
The difference in approaches can be summarized fairly simply: when you're building a layout engine, you focus on the ability to morph, to be a tool for building tools as efficiently as possible; one tool to rule them all (all hail Tolkien). By contrast, when you build dozens of pre-fab themes, essentially modified individual "clone-forks" of one another, you're focusing on scaling your output, and the number of situations each of out layout themes can deal with out of the box.
On one hand you're an end user/consumer of a single-purpose built mass-produced product that will expire, on the other you're an end-power-manager of an engine to build layouts yourself over and over.
See the problem? It may seem counter-intuitive but when you need to build one engine to rule them all, you need to be serious when factoring in efficiency, capacity, flexibility in as many use cases, functions, tools, and interface elements. It's going to be used thousands and tens of thousands of times in many different situations and sectors. You put a ton of effort into engineering a singularly elegant solution.
Be clear about what you are and what you are not
Are you a rapid development environment? Are you an engineering tool? Are you a no-training newbie tool (not that there's anything wrong with that)? Are you a power user tool? Are you an engineering code environment? Netgen Layouts sits just above the Symfony functionality code layer with a well thought-out suite of layout types, content modelling, presentation tools, and most importantly, a tight awareness of its parent CMS content, Commerce content, or other content source, including how to call it for almost any use case you'll come up with.
To my question, then, it is first and foremost a Presentation Manager focused on layout and UX interactive building. The deeper suite includes an almost limitless scalability for your own content type modelling and CSS crafting. For most use cases so far, those two creative development areas will take most day-to-day use cases everywhere they need to go to get their job done and site presentation perfect. The richer you model your content types you've integrated with the CMS layer, and the deeper and more involved you craft your CSS, you're off and building very quickly and very creatively.
It's going to be used thousands and tens of thousands of times in many different situations and sectors. You put a ton of effort into engineering a singularly elegant solution.
Broaden your team's abilities
In fairness, similarly-positioned "page builder" types of platforms do exist. Typically, these are baked into content management systems or prepared "themes". That puts your design and layout presentation team into a clear box -- this is the theme, this is what it does, be happy.
Netgen Layouts puts developer-like tools into your design and layout presentation team's hands. You're blurring the line in developer and designer output which is a good thing. Now your designer has an entire dimension to work with. Rather than being obstructed by the prepared template code model, and developer-level management, your design and presentation team moves into interface modelling all on their own.