No one can deny how much of an impact Tenergy has had over the years. But it has become less relevant as time has gone on. The price has ballooned massively, other manufacturers have closed the performance gap considerably, and it could be argued that the plastic ball benefits from a different type of rubber (I know not everyone would agree with that last one, but that's how I find things at the moment - very personal thing).
It's still great, but worth paying almost double the price over the latest ESN? Not for me. And I honestly don't care that the pros use it. First up, the pros in general have different performance needs to me, and different cost considerations. I evaluate my needs based on my highly average amateur level and the fact that I have to pay money for rubbers. Secondly, there could be many reasons for so many pros using tenergy unrelated to performance alone. Sponsorship is a big one, plus Tenergy made a big splash when it was first released. Although the gap has closed since, the pros won't switch unless it's really worth it. And although we are seeing some interesting changes now (Koki Niwa), even if ESN produced something which was just as good overall, why bother switching if the overall benefit is zero?
Personally, I think it's better to look at the next level down from the top 50 pros and see what's going on there - it becomes slightly more relevant to mere mortals such as ourselves. You still see lots of Tenergy, but there is more variety there. Lots of Rasant in the Bundesliga, lots of Rhyzm and MX-P in the British League. These guys are still MUCH better than me, and if they don't need Tenergy then neither do I. If I use ESN, it won't hold me back. So why pay twice as much? It doesn't make sense to me, for what I need. It only made sense when Tenergy was doing something no other rubber was, and when it was comparable in price. I can get a full season out of my Omega V Asia for £26 (if I look after it), and I play better with it too (YMMV of course), so that's it for me.
Of course, I can totally understand why someone else would be happy to keep paying the £45 for Tenergy too, and that's their choice. Everyone evaluates value for money in their own way.