In the cases where we have objective measures (like memorization contests) we see records being broken all the time (which is as we'd expect). A lot of this can be attributed to improved general intelligence, but we'd expect that to be correlated with creative skill too. Are there any measurable world records from the Elizabethan era that still stand?

The damning point here is that you are willing to bite the bullet and say it applies to sciences as well, where we would, contrariwise, naturally expect the earlier a scientist to live, the easier it is to make incredible discoveries and pick up low-hanging fruit. Only an early scientists has a hope of discovering, say, gravity. Or an early mathematician something like calculus. You have to live as early as Parmenides if you want to discover something basic and extremely important like 'the moon is illuminated by the sun'.

You're measuring something here, but I don't think it's likeability. Newton may have been more historically important than Einstein, but no-one would prefer the former's theory of gravity to the latter's. If Shakespeare got pretty close to the perfect tragedy, but there was a slight refinement of the form from the 19th century that's better (if less significant), surely people would prefer to watch that, and count themselves fans of that author.