It's just me, I know...
But, what I always look for is not the creativity, investment, and market justification for the major manufacturers to pony up new, prototypical...or not...accessories.
Rather, I eagerly go through each new issue of our hobby's publications, read the forum postings, visit other layouts of fellow hobbyists, look forward to a good 'bull' session with a few friends, participate in a club with fellow hobbyists who like to think 'outside the box' or creatively, etc., etc., etc....in search of ideas, articles, examples, and the like of how common "toy-like" accessories have been hi-railed, how mechanisms have been applied to new animation/accessory ideas, how gadgets and gizmos from entirely other hobbies...e.g., radio-controlled boats, cars, planes, drones, etc....can be applied to our own hobby.
If I thought the seed of all creativity for new accessories, more prototypical accessories, more reliable accessories was the handful of major manufacturers,....well, I think I'd box up the trains and find another hobby.
I remember the run of animated accessories that Lionel did a few years ago based on those found on the layout at The Choo Choo Barn in PA. Well, everyone will have an opinion about the merit or success of those, but the fact is the creativity did NOT come from Lionel staffers, as many of the original iconic accessories did in the first few decades of the last century.
New accessories for mass marketing....Legacy, Vision Line, Conventional, or whatever...require a solid business case for the tooling/marketing/advertising/etc. investment. As other threads re engines and rolling stock of precise prototypical fidelity on various wish-lists have opined, you may wait more than a lifetime before you see it in some affordable form from the major manufacturers.
So, as I said, this perspective is probably just mine alone. I'm good with what's out there. I've got a 'bucket list' of projects for the layout that include hi-railing accessories, creating new animations with old mechanisms, etc......ALL of which came from friends, fellow hobbyists, other layouts, articles....dreaming....about what I can do to achieve what I wish for.
People like Lee Willis...just one of the first examples to come to mind...are my heroes of inspiration.
Worth 2 cents, I know.
KD