A copyright of a few years would better reflect what has been going on in the daily life since 70's-80's. If you grew up then you would see films of only few years back on TV at which point you could tape them for yourself and your friends. Anything that was broadcast immediately became effectively free: there was always someone who had a copy you could borrow or copy yourself. This gave the industry a lot of time to milk revenues from the cinema and then home video until everyone had it from broadcasts.
With a few notable exceptions, I don't see content from five years back making a huge cashflow, not to mention ten years. Thus copyright could be a paid privilege.
You would get the copyright for the first year for free. Then it would cost more each year to maintain the copyright for one more year. Let's take a small percentage of the first year's total sales for a given piece, make it the cost of copyright for the next year and for the following year, add the same percentage to the previous cost of copyright.
We would therefore effectively be taxing the practise of hoarding content under copyright.
At the same time income from the content would fall so the markets would reach a point where it would cost too much to keep the copyright in effect. The content business could make their own decisions per each piece of content. They would extend copyright on the most popular films and music while let go of the ones that don't sell too well.
All this would benefit everyone and make the copyright monopoly vs people's rights closer to a balance.