Scratch model making has certainly become a lot easier over the last few decades. Making a model of something required a considerable commitment to making the parts of it. Wood was one of the most enjoyable materials to use but it was difficult to create a realistic looking model. However the introduction of plastic has meant that pretty much anything can have a model made of it. This can also look extremely realistic with the right painting skill and transfer placement. Model kits are widely available by companies like Airfix and Masito. It has also meant that the building of the model railway system can now be huge and remarkably detailed.
What about if you need to have something bespoke? That can be a problem. You can scour the internet and model shops looking for that one piece that is going to make all the difference (which sounds a lot fun doesn’t it?) or you can make your own through the use of silicone moulds.
Silicone moulding UK for industry is covered by https://www.meadex.co.uk/silicone-moulding/. You might not need to use them for your project, as they are an industrial sized firm and they deal with large scale projects. But using silicone on small scale moulding is pretty much the same process and you make yourself the perfect answer to move forward. Landscapes, equipment pieces, diorama additions, all can be made via a skill with moulding.