I think its a mistake to trust one website with statistics and base a debate off it.
"It is worth noting a few possible anomalies with these statistics. For example, overestimation may occur with page refreshes, loading resources like css or JavaScript files, and feed readers may be counted."(http://www.techrepublic.com/blog/programming-and-development/should-web-developers-keep-up-with-browser-statistics/719)
Here are some other sources:
w3counter.com/globalstats.php
gs.statcounter.com
As long as those numbers don't change significantly, I wouldn't hesitate to predict, who's winning. If HTML5 isn't hardware-accelerated on the majority of browser/operating system combinations, it is too slow compared to Flash, to have any success for now.
At this point in time - flash games are undoubtable more accessible than html5 games (i dont think anyone is debating this). So why do we make html5 games? Because it is the way of the future (i dont think anyone debates this either do they?) - were embracing new tech!
w3schools.com/browsers/browsers_stats.asp
(Now this shows a trend!) - And if it continues growing like this, it wont be long at all.