If you look at the performance of all the Denuvo titles, not just one or two examples, you'll find no major anomaly in their financial performance that suggests that the DRM helped them outperform similar past titles. None with any major statistical significance. It means DRM either has no effect, or more likely a minor effect on the market. The fact that there are multiple Denuvo games on market only strengthens the arguement.
You can observe trends across several games though. Thats a lot more backing than the opposite view seems to have.
The idea to post Steamspy numbers is to show that games on PC sell without excessive DRM. Denuvo won't save anyone.
We can play tennis with Limbo's numbers as much as we want, and then I can just provide additional examples.
None of you are even remotely close to realizing how the statistics on this work.
You absolutely can't observe "trends" on such a high level and then attribute it all whether it has or has not DRM. There are way too many variable for proper attribution, and historical data has much too noise for you even achieve a reliable p-value at ridiculously high expectation for uplift. Same goes if you want to prove that it has no effect. Unless you can A/B-test it, sales data like Steamspy simply won't cut it, unless DRM would achieve impossibly high conversion rate, which it certainly does not.
Which brings me to the second point, which is your expectations. Most of you keep repeating the word "significant effect", so please tell me what's your expectation. 10% increase in sales? 5% conversion of pirates?
What you don't seem to realize, that even a relatively marginal percentage, like 0.5% conversion or 1% effect in sales would be a considerable uplift in revenue, and surely worth the cost of the DRM (including license and implementation). But that scale of effect is something that you certainly can't prove reliably with data available to the public.
So in short, if you want to actually prove anything, first read a bit on the basics of statistical analysis and tests, and temper your expectations to a realistic level that would be profitable for a publisher.
So I can hear you ask how do you then prove the effect? Well, first step is to prove that piracy does not have an effect on sales (proving the opposite is easier, than it being true), which you can contact a few actual statistics companies like EEDAR or SuperData. Or if you have already been able to find correlation (not causation) between the availability of a pirated version and a change in your measurement, you can already know that there is correlation. Case in point:
I can also vouch for this drop from first hand experience of seeing sales curves, but because nearly all sales data is bound by platform agreements and publishers interests, you will not see this data publically.
So based on what you already know, and being able to track for example share of pirates showing up in your metrics, you can quite reliably know whether there is an effect or not. That should be comparable against the cost of the including DRM, so if the system is being retained after a few uses, in today's data driven environment it would be safe to say it's because publishers/developers can quantify a net positive effect on their revenue.
Now, I as a consumer don't especially like any form of DRM and certainly care very much about preserving games for my own enjoyment and for the future of our industry. But, it's very much a complex matter of factors that both affect both developers and consumers negatively and positively. So, for the sake of discussion I don't really have a personal stance one way or the other, but I can confidently say that there is absolutely an effect that if diminished, can easily result in a quantifiable net positive for the developer/publisher.