That's all within the realm of possibility, sure. But keep in mind that the affluent could simply buy a drone(or what-have-you) with all sorts of bells, whistles, and 10 years of improvements to security. The amount of work necessary to DIY something that even begins to approach the capabilities of something built by a company that knows what they're doing would be extreme - I'd argue insurmountable in many cases - even with 10 years of improvements to manufacturing and the availability of components.