They don't, nor have I seen anything like that discussed by Macrium, I suspect for the reasons Froggie already mentioned. And I for one would prefer that it stayed that way. Companies tend to offer better products when they maintain a narrower focus, in this case quality backup software. The cloud storage market is already well beyond saturated, offering a variety of price points, capabilities (API access, functionality vs. security design, replication among peers you control vs. storing data on someone else's infrastructure, etc.), so I personally don't see what additional value Macrium could really add to what already exists. I do however see how much of a potential distraction it could create. Designing a cloud infrastructure that offers proper resilience is no small undertaking in terms of expertise required, design work, cost, etc. At a minimum, you need multiple sites and very high speed links between those sites to offer fast replication. And then you need more expertise, design work, and cost to offer proper security for your cloud infrastructure, which is arguably even more important than resilience especially given that we're talking about storing backups here and that not everyone chooses to encrypt their backups. And that's all before having to deal with the regulatory concerns around storing this kind of data (presumably) within the EU, which has some of the strictest data security and privacy laws in the world, PLUS the concerns about storing data from international customers and therefore potentially having to either comply with THEIR regulations (which may conflict with the EU's) or else face legal battles with those customers or even their governmental agencies over refusing to comply. This all creates not only additional technical concerns but also legal liability considerations.
At the end of the day, Macrium lacks the customer base and therefore the potential for economy of scale enjoyed by companies like Google, Amazon, and Apple, and therefore a "Macrium cloud" would almost necessarily be either more expensive for the same quality of offering, or identically priced for an inferior product. Either way, I don't see how Macrium could compete with established offerings here. So I hope Macrium keeps their focus on Reflect.