The arguments surrounding the salary differences between engineers and sales people have been running for as long as anyone can remember.
All sales people used to have to be engineers of some sort if they were to have credibility in front of the customer. Sadly however those days have since passed but, rather than complaining about the salary differences, become a salesman yourself? Many have done it before and been hugely successful.
Yes the salary will be better and the vehicle will be more luxurious (with an expensive personal tax bill too) but sales is black and white; numbers will immediately show if that person is working and/or successful. Consequently job security is not what you would enjoy as an engineer.
Unfortunately, the choice is money or job security - there are very few jobs in this industry that can provide both