"My customers" as you call them are not really "my customers" in reality. No one owns "customers". Yes, most raceways treat customers fairly and equally. However if there are not enough customers willing or able to pay for track time, purchase parts, or become a "regular customer who spends his money at the track", the raceway goes away.
That is the way it is in any business. It is nice that you spend your money at Chris and Lenore's BP because they treat you nicely.
Unfortunately for most raceways, most people do not spend money at the raceway for your self-proclaimed reason, as that does not really happen too often. If that really happened on a regular basis, we would not be having this discussion at all. We would have hundreds of raceways, manufacturers, and customers... if all it took was "treat people nicely".
The issue why slot car racing "died in the sixties", is multifold. It is the same reason it is dying on the vine now.
And it revolves around money. Small numbers of "customers". Not enough as a whole to make up a sufficient customer base to keep the track (business) viable. Most raceways do not make money. (Don't believe me? How many tracks open and close within 18 months?) Where we are located there is no other slot car raceway for about 400 miles west, 800 miles east, or 1,000 miles north. And if Buena Park is the only raceway in SoCal is that good enough for you? So I ask you, how is that working for ya? Again it comes down to money. If investors (business owners) saw a potential to make money and get a return on their money, slot car racing would be thriving instead of dying.
So the hard and proven facts are, the ownership (investors, business people) cannot support it any more by himself, so the (investor, business owner) closes shop and plays golf.

No promotion, support, or advertising from the self-proclaimed cottage industry manufacturers. Manufacturers refuse to support or promote the industry they are a part of for various reasons. The main one is money. Not enough money in the till after expenses to do anything but produce the products. And guess what? Most of the time the manufacturers do not get their investment back. Again, lack of customer base to support continued production of parts. So see paragraph previously for reason why the manufacturer decides to not produce anymore.
So unless this industry as a whole, from the manufacturers to the raceways to the customers, spend sufficient money to get more customers this slot car racing thing will just fade away. Sure there will be a few places here and there. But not enough support from all factions mentioned will make slot car racing go the way of blacksmithing as Marcus stated. When raceways fade away (showcases for products) there is no reason to produce products (items for sale or use by slot car racers). No customers, no products, no raceways. As the customer base shrinks, the reason for parts declines and the reason to carry parts fade and the reason to keep a raceway open goes away... Again, how is that working for ya?
So if you are happy to see slot car racing become extinct for the most part, continue doing what you are not doing. (Comments and opinions are not meant at anyone in particular, the "you" is slot car racing public in general. And that is the raceways, the manufacturers, and the customers)

