Complex does not mean how much electronics is inside – it may be pretty simple to make an “impressive” product with out-of-the-box modules (both HW and SW wise), but do not expect it to work under too many conditions and rather do not put it even under legal market tests (instead claim the modules are certified and you only put them together 🙂 ).
Or if you are putting together a data center with tens or hundreds of racks, sure, there can be significant debugging, but you wouldn’t probably claim you developed it – more like constructed it.
What about electronics in large science experiments? Indeed there is something cutting edge about this, yes, the edge, but not so much around it. If it is supposed to work in extreme radiation and magnetic field environments, it can be tricky enough on its own (or does not have to be – depending on what you start with), but otherwise, you can use anything, and it can also cost almost anything, and you can also excuse almost any deviation – it is a research.
Can a rear combination lamp be a complex electronics product? Yes, absolutely. Things like extreme EMC, cost, no serviceability, defined mission profile, development process requirements, safety concerns, styling, legal requirements, lifetime under climate variables, testability, traceability… even things like possible leakage of aging plastic connectors all add up to a fairly complex problem. Complexness of electronics is defined by how many dimensions are there to consider in the design and how tightly they determine the final product. Surprisingly, an engineering tool can be less of an issue than a household product.