I'm not sure why you think the age of the medium has anything to do with it
Violins have been around since the 1500's. That doesn't change the fact that a reasonable quality student student's violin costs around £100-£150 but the market is awash with poorly-made and bad sounding cheap violins for under £50. These are sort of products that look a bargain at first, but make it harder for a student to learn because they're shoddily built, and that's discouraging. The justification often offered is "It's okay for a beginner", but in reality it's not. Even someone starting out needs an instrument that helps them get the most from their efforts. Something that holds them back from enjoying what they're doing is a bad investment. In the end the product has no residual value. The above is something of a parallel to cheap audio visual gear. Turntables is just one example. It's a product that's in vogue, and so any factory in China that can turn its had to making a turntable smells a potential profit. Unlike a violin though there's no opportunity to easily go off and hear a virtuoso performance or even just a good one. For this reason many buyers seduced by cheap product that trades on semi-nostalgic product names will rarely ever experience anything better.
Vinyl as a medium has its limitations of course. But the fact it has been around a long time certainly isn't one of them. It is fully capable of faithfully storing very high fidelity sound. So when someone says they want a vinyl based audio system (turntable, cartridge, amp, speakers and cables) for £300 then £100 for a record deck won't do justice to the medium.... not by a long way.
...... (wasn't me either.... but posting tempting links on forums normal leads in someone snapping it up...) 
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