There are
new record players being made, bought, sold all the time at present, and I'd expect many of those 16 year old you spotted in the queue outside Piccadilly Records to be alive in 30 years. As a 48 year old I hope to be around then too!
Tony, Technics' discontinuation of the 1210 suggests that those 16 yr olds won't have the choice of deck you had and anyway, young man, it maybe sooner than you think
http://menmedia.co.uk/rochdaleobserver/news/s/1148346_shock_figures_show_towns_death_divide
It is also worth noting that as a 48 year old I enjoy much music that existed before I did, jazz, classical etc, i.e. I own many records that are either older than myself or were pressed when I was far too young to buy them. I am far from alone in this, so it is safe to predict that those 16 year olds will expand their taste in similar ways.
This is
as daft an argument as saying a Kindle will render books obsolete. It just won't. Out of X number of people there will always be Y percentage who just prefer a nice big hefty book to squinting at a screen, and a smaller Z percent who not only think that but want to hunt down the collectable 1st edition in pristine condition. As a record dealer I've only ever been interested in the last two groups.
This is not an analogous argument as I am sure you appreciate books remain very much the common mode of access to such information whilst vinyl is now somewhat rather further down the line to obsolescence.
I have two.