Bigger firms still take on trainees/apprentices and train them up.
Trouble is that in the modern economy, there are a lot of small firms, lots of firms that are little more than "one man bands" or just a handful of staff.
A very small business will not have the resources (time nor money) to train youngsters from scratch as they're very labour intensive to teach, supervise, check, correct etc.
I was trained in a small accountancy practice straight after getting A levels. I was a pure "rookie" with no accountancy knowledge/experience. The firm had 20 staff and took on 1 trainee every year. So at any time, out of those 20 staff, 5 were trainees as it typically takes 5 years to do the exams and get the requisite experience etc for a school leaver. So a quarter of the staff were being trained in some form or another by the other 15 staff.
It was hard. Especially in the first couple of years, it was almost 1-2-1 training from other staff, who were also trying to do their own work as well as training us trainees, checking our work, finding our mistakes, etc.
I started my own "one man band" practice back in 2000. It grew very fast. I took on a school leaver trainee. It was a nightmare. I was busy myself doing my own work, and ended up working longer as I was losing so much of my daytime working in trying to train her, supervise her, keep her busy, check her work, organise her courses, etc. I really regretted it after a few months and my work was harder rather than easier. It took a good 2/3 years before she was fully competent and confident and I could start relying on her to work without constant supervision and checking. Then she upped and left, just as soon as she was actually becoming an asset! Never again.
The economy has changed. We have fewer larger employers, and the smallest employers don't have the support/resources to take on rookies.
A typical 1/2 person web design firm simply can't take on a raw recruit as it would spread the existing owners too thinly not only in time to train them but also the huge costs of training.