I have to say that this post is coming across as very judgemental against today's parents. I have four children, now aged 22, 20, 18 and 11. In fact, they have all recently had they have all recently had birthdays - my eldest, DD1, has her birthday at the end of July, whilst the other 3DC have their birthdays in August, so I certainly know what having children who are young in the year is like.
The changes are not just down to parents spending all their time on phones and watching TV and not paying their children enough attention. My eldest 3DC all started school the January after their 4th birthday and spent the first half-term at school until lunch-time, so they were all 4 and a half before they were at school all day. They could all attend the local nursery at 2.5 years, provided they were either toilet trained or, if not, I was prepared to go down to the nursery and change the nappy if it was soiled during a session. Fortunately, my 3DD were all toilet trained by 2 years and 3 months. My son was marginally later but I only ever had to go down to nursery once to change his nappy.
By the time my youngest DC was at nursery, nappies were accepted. When DC4 started school, she started in the September - 10 days after her 4th birthday. Within 3 weeks of starting, she was attending school all day.
These were just obvious changes that, as a parent, I noticed. I sent my children to nursery more for the social skills they would learn and so that they learned to be separated from mummy. They were all brought up to love books and story-telling. However, when DC4 was at nursery, much more detailed records were kept, with detailed pictures and notes depicting which targets had been met and which areas needed working on. This book was transferred to Reception at the local primary school - ideally by the end of Reception, all the targets had been met, irrespective of whether the child was just 5 or almost 6.
When my eldest 3DC were at school and before I had DC4, I trained and became a childminder. For the most part, I chose to mind children who were under 5 (pre-school), as I wanted to spend the time on my own children after school. I loved childminding and spent many hours chatting, reading, playing and interacting with the children I cared for. I had a short break when I had DC4 and then resumed childminding.
However, I gave up when DC4 was about 2 for two reasons. Firstly, I felt I was compromising my own child to meet the needs of other cared-for children and, secondly, there were new rules that were coming in that required childminders to keep detailed records of achievements and milestones met and examples of how different criteria were met. To me, this was not what childminding was about. I had always kept a "contact" book, where either the parents or I could write messages or notes for one another when necessary, but my belief was, and still is, that if a parent wants their child's achievements monitored, then they would choose to send them to a nursery rather than a childminder.
So, to summarise, there have been more targets that have been set in the past 10 years and nurseries have had to be more accommodating. Not all parents are lazy, as one or two of the previous posters would like to believe. Children are starting school at an even younger age nowadays.