The decision to eliminate use of subways was a Stern company decision all the way back to 2001.
There intent was to make cheaper, affordable operator games that were more reliable and less complex.
It is called a "top down" method, similar to the designed games such as T2 and Getaway.
Hence, the removal of this type of feature very early on.
This standard for the most part has remained intact today, and other types of old style innovations removed from games.

For example, return lane kickbacks.
Removed, for cost reasons as they were considered "unnecessary features".

It is unfortunate that some people do not want to understand pinball history, designs, or developments, but rather insult. If they did they might better understand why things happen the way they do in the industry, and move beyond the basics of playing games.

These become the caretakers of games for troubleshooting when the original designers, technicians, and manufacturers are long gone.