The debate about V-scale vs model railways is a bit of re-direction.
For starters, you need to buy the hardware to run a train sim and to do so adequately it needs to be more than a £300 budget laptop from PC World. With a model railway you have a solid 3D object which you can pick up and handle and has real weight and inertia. V-scale will only ever be a set of 2D pixels on a screen, even for those who use a VR headset. We can have long prototype routes vs. a 16' x 10' layout but again you have the ambience of a world you have created, the smell of the flock and enamel paint and ozone from the locos as they go by.
The comparison is a bit specious in other respects. As FS19 has come up a few times, a real farm would cost far more than a model railway to buy and equip but FS17 was recently on sale for £7.99 and FS19 is launching at £29.99. Buying a real rally car and using it to compete in real events would cost a small fortune, but I would only ever expect to pay £30 for a rally game on the PC.
The real factor here should be what other computer games or simulations are selling for. Each has their own business model, DTG has been mentioned a few times - their annual core update is free but the money comes from selling DLC that people actually want to buy. Run 8 uses a similar model and their routes are very expensive but unlike Trainz they are catering to the high end of the simulation market, with high fidelity physics and other operational features signed off by real railroad engineers. And while there may be unexpected surprise at N3V Towers (sorry, PO Box these days) at the number of people who have just gone "sod it" and paid the $70, that price tag is unlikely to draw in much new blood either.
I should add that model railways generally are an investment, the value of your collection more likely to go up rather than down. Wish I'd hung on to my old stuff from the 80's could have made a killing selling on Ebay, hey enough to fund buying TRS2019. But software is worthless - you don't even really own it, can't resell - certainly on PC with DRM - and you generally can't even get a refund or take it back to the point of purchase if it's rubbish.