Then colored pastels came along as the "tool of choice"... lot's of artists made the switch.
Then came markers.
There were some artists who didn't like drawing with markers, they liked the subtle looks they could achieve with pastels... they didn't make the switch and found themselves looking for a new job with old skills.
Who would have thought that tools that have been around for ages would go the way of the dinosaur.
Who would have thought that skills like hand lettering and figure drawing would not be needed to be a designer and that instead of clients taking a leap of faith when they saw a drawing of what their would look like, that today it's "what you see is what you get".
My point here is that you have to be on the lookout for new trends and not be caught up thinking that things will stay the same.
I called an associate of mine during the period of time that some of us were getting into the computer. "What are you up to" I asked.. "Selling car stereos" was his reply. I laughed. I thought he was joking. He wasn't. He didn't make the switch and found himself unemployed.
I used to have a machine called a Lucy. It's official name was Camera Lucidia. If a client gave me a photo of their product, I would place it in the machine and it would project the image onto my paper. It would cut down on the amount of time it took me to draw things and it allowed me to be more accurate and more profitable.
I couldn't give it away when the computer came along!
Also keep an eye out for new areas to increase your revenue stream. When I saw that people were cutting down on advertising and putting their money into the web, I started offering web design. When banner ads started to become popular... I added Flash to my "arsenal".
Read the business news, keep your ear to the ground. Keep an open mind to change. Adapt or die.