If you are thinking along the lines of the first example, eg. the "I know html and css, I can build a website with pictures and operating hours for a mom and pop shop" developer, this market is shrinking with platforms like wix and squarespace where regular people can build these sites and maintain them easily and for cheap. Not to say you can't still make a living doing this, but it is something to be aware of if it is the route that you choose to take.
If you are thinking more about the second example, yes, there is a high demand (and rapidly growing market) for this kind of developer at startups and fortune 500s and everything in between.
Overall, the answer is yes, web development is still a growing field and it is absolutely a viable career choice, but it is important to keep learning and be aware of the market and adjust accordingly