Why can’t I continue “reading” an article by having it read to me, in real time?

For example:

• Someone sends me an article to read via text.
• I tap the link, open it.
• Start reading.
• 2m later, alarm goes off, have to start walking to a meeting.
• [double-tap on the screen], and the phone immediately recognizes that I am asking it to start reading me the material on the page.
• [something on the phone] starts reading the same article to me, where I left off, so that I can put on my shoes, get my keys, walk out the door, and amble towards my destination, without missing a beat.