Haze, it really depends on what the devs are interested in and what their expertise is.
I am interested in a lot of things, but I don't have much experience in digital hardware. Hence I don't make emulators for MAME, but there are other areas where I can make contributions. Devs who can work on emulators are going to primarily work on emulators, because that's the most fun thing to do in this project, IMHO. If there is someone out there who is interested in pinball and knows enough about it, then they will work on it, so long as there isn't something that is more interesting for them.
Emulating handhelds is still emulation, and thus gets a lot of interest from the devs, pretty much all devs. Simulations just don't get that type of treatment, neither does a port to Android, and many other things that aren't seen as critical to 'preservation'. I've had many devs say to me they do not care about screen simulation at all, yet I feel it is an important part of these systems, equal to anything on the digital side, esp. being able to reproduce the raw analog video signals. It is an example of MAME having to step outside the digital world and figure out how to deal with analog functions. It is actually not quite unlike the LaserDisc fiasco. Electromechanical interfaces are a difficult thing to tackle. MAME doesn't simulate joysticks, steering wheels, and other inputs with a virtual 3D model. Is pinball different? What is the extent that we simulate things? How accurate should it be?
I don't know if it is just inexperience in engineering mixed-signal systems or something else, but devs are going to have to learn to compromise and accept imperfections in analog simulations, because they cannot be perfect. There has to be a willingness to accept something as 'good enough' while keeping a door open for better systems in the future. I am not arguing for HLE here. I don't think it ever helps. I am just saying that there needs to be people interested in making the simulations and the devs need to be open-minded about accepting them.