Land-vehicle production is extremely risky

The process of assembly-line based land-vehicle prduction

Land-vehicle production involves 4 sequential aspects

1. Designing the vehicle
2. Manufacturing the vehicle
3. Selling the vehicle
4. Providing after-sales service

A land-vehicle is a complex piece of engineering.
Producing one at a saleable price
requires the economies of scale afforded by large scale production.
In existing practice, a land-vehicle is designed by a large design team
working on different aspects over a few years of design time.
Subsequently the design is manufactured in a dedicated assembly-line factory.
The manufactured vehicles then have to be sold
at the rate they are manufactured.
Dealerships have to be setup for the sale process
and service centers have to be setup to provide after-sales service.

The investment required for assembly-line based production

The investment required to produce a land-vehicle consists
- paying for the design team and associated prototyping costs
- creating a captive manufacturing factory
- operating capital for the factory's material inputs and labour
(though manufacturing can be outsourced in an "asset-light" approach)
- advertising costs
For a car this investment runs in the ballpark of $1 billion
and return on investment depends on the level of sales
in a highly competitive market.

Design updates are very slow

As things stand today, land-vehicle designs are revved by manufacturers
in sync with production cycles which are roughly 5 years in length.
The rate of innovation in land-vehicle design is therefore quite slow.
and the ability to design and manufacture a land-vehicle viably
is the exclusive domain of well-established, deep-pocketed production companies.