The direct connection model makes a lot of sense, between the rapid change in battery technology and with the advancement of wireless technology , including what may be a game changer, local 5G technology, that will (in theory) resolve issues with latency on current Wifi or Bluetooth implementation. I had one person tell me that radio control wouldn't work, that having the signals go over the rails is 'the only way to go'..and they had Legacy! (Legacy transmits its signals using the ground wire in your house wiring, it is why legacy and tmcc engines have an antenna in them..). Batteries are heading not just to long life, but also rapid recharge (yeah, I know, the cars talking about 80% recharge in 15 minutes are talking about 800kw charging stations, which is like the power of 40 houses with 200 amp service, but that is rapidly changing as well). Likewise, the cost of implementing this will change as technology advances, to give you an idea of scaling things about how DCC that once had trouble fitting in an HO scale engine these days is being put in N scale engines (and I wouldn't be surprised with Z..).
The real question might be around the bells and whistles (figuratively and literally!), advanced sound or the kind of features you might find on a vision legacy engine and the like. The real hope is that these wireless systems go the DCC route and are an open standard, rather than the proprietary systems we see with DCS and Legacy, among other things that will bring down the price. Among other things, this also will make converting existing engines over relatively easy, similar to adding DCC to a non DCC ready engine from what I know.
And the benefits are obvious, no tangle of wiring of power and command systems, no issues with track getting dirty, shorts, etc (we might still have wiring for things like switch machines, to bring power to them, but they could easily be controlled via wireless control as well, or accessories and lighting, but that is not exactly most of our wiring).
There are things working against this vision. For Lionel and MTH, they have a lot of vested interest in maintaining their proprietary systems, and even though for example Lionel is moving to where you can control a legacy engine or LC2.0 via bluetooth, I doubt they are heading to battery technology any time soon, for a lot of reasons (among other things, transformers are still part of their business line), and I doubt MTH and Lionel would join an open standards thing.
