What are you talking about ? Inform yourself before passing such a statement. A lot of people have made ROI. Here is a screenshot from a third party cloud mining review website, which invests in various cloud mining companies and report about them...
Source: www.cmmonitor.com/24-cloudmining-website.html
Here is the Tx ID of all the payouts made by CMW in last six months: www.cloudmining.website/payments.php
How many cloud mining service dare to publish their payout details ? If something is scam, call it a scam. If something is legit, learn to appreciate it.
It's true that lot of people had made ROI from this ponzi and others too but you must understand, ROI from a ponzi doesn't make them legit. Only ponzi publish their payout details to make more people invest. For legit site, there is no need to. The their party site doesn't invest in all site, they only calculate. They run the site to get referral links not to help anyone.