Since 3D-printed models are not made within an enclosed mold, any and all overhanging features have to be physically supported in some other way during printing, normally by a sprue. This means that the more geometrically complex the model, the more overhanging features there are to support.
It also means that the smaller the model, the more packed (close together) the supports will be. The support array can easily overwhelm a model with attachment points in very unfriendly places.
Vendors are well aware that the support array, attachment point location, and support density are critical factors in producing a model that can be printed at all while at the same time be practical for the typical modeler. Vendors work hard at trying to strike a balance. Sometimes, vendors are successful at striking that balance. Other times, not so much.
Especially for small objects, that balance cannot be achieved with the tech presently available or affordable. This is why many vendors who produce a model in 1/350 scale don't offer that same model in 1/700. Their 1/350-friendly tech simply can't produce the model in 1/700 scale with supports that can be removed by the modeler without damaging or destroying the model. Conversely, vendors who offer an amazing catalog of superb small models, aren't also offering 1/96 scale turrets; their 1/700-friendly tech simply isn't optimized for larger objects and therefore can't print large objects well if at all. To offer both large and small models, vendors have to have different machines optimized differently, one kind of printer for small models and a different kind of printer for large models. Many vendors simply can't afford to have a variety of machines on hand to be able to produce both large and small models, at least not until sufficient revenue comes in to support the acquisition of more and different kinds of machines.
For example, a B9 Core 550 (click here) is a 3D-printer optimized for small objects with very fine detail. It is typically used by jewelers but a fortunate few scale model vendors have one, too. The machine costs upwards of $14,000 USD with kit. In order to meet typical production demand, more than one printer is needed. Very few vendors can afford such a machine let alone more than one. Those who can afford them rarely use them to produce models that sell for a few dollars each. Machines like that are normally used for far more cost-effective purposes. There are exceptions, of course.
On a few occasions, customers have told me, "Hey, I just can't remove the supports from your model with destroying it. Is there anything you can do?" And sometimes, the answer has to be, "Yes, I removed the model from the catalog." Until better technology becomes available (and affordable), achieving balance between creating a properly supported model and making one that can be used by the typical modeler isn't possible. But the technology is rapidly maturing and therefore, achieving that critical balance gets easier with each new generation of 3D printing tech.
Very few 3D printing vendors can print a 1/700 scale Oerlikon with shield. Kudos to Bunker Studios for being able to bring these models to market.