I'm not advocating for a single provider, and I'm not necessarily advocating for cloud hosting as a solution, I'm just pointing out that in this case the cloud fared better than practically all of the self-hosted systems
It's not the same OWA that one hosts on-premises. That one's still vulnerable even if it's hosted "in the cloud".
On a different note, if they could prevent this in "the cloud version", why couldn't they -- why didn't they -- prevent it in "the non-cloud version"?
Even if we assume that they did create two independent systems, there is no reason to assume that two products developed by the same company in tandem serving the same fundamental, lucrative use case should have material differences in quality/process. That there were multiple trivially exploitable, catastrophically effective vulnerabilities that were unknown for 8 years and that Microsoft never discovered themselves (they discovered it by realizing somebody else discovered it and was using it) should indicate that their cloud product is equally atrocious even if we assume that these were distinct products and thus would not be affected by the exact same bugs.
In conclusion, as you say virtually every computing system out there is a house of cards, so there is no reason to assume that consolidating on the cloud and letting one of those groups of people focus will result in anything other than more houses of cards, except in this case being used on an even juicier target.
The point is not if the Cloud can defend against a very sophisticated attack, the point is whether they can at least do a better job than what those big companies are doing.
And the answer is really easy: Fortune 500 are at the Stone Age of security (among a lot of other computer science topics) so of course the Cloud is doing better. It’s not even the same world or the same order of magnitude.
And the abyss will become bigger and bigger because it’s becoming more complex. There is no way a Fortune 500 company can keep up with the complexity of what AWS, Google or Azure is dealing with, and the new tech world we live in. And it’s also quite stupid, that’s not your job nor where you will be making money. Just concentrate on the app/code that is indeed your core job, on top of solid and proven Cloud services.
Also, you talk about centralisation and the issue of a single provider, well, here’s the actual joke: the level of centralization and concentration is way, way bigger internally than if it was on the Cloud. Most of those Fortune 500 companies have only a few datacenters. Although they are international, some even have datacenters only in their local region of origin, with zero region/local hub of some sort, as crazy as it may sound.
And most of those Fortune 500 companies have only one provider for each of their key component.
If they were on the Cloud (and they will be, eventually), reversibility and transferability is « built-in » almost, because it is an actual feature, or because everything is way more standardized, or just because moving into the Cloud, you will think from the start about how to move back or to a different provider. And in any case is much much better than the state there’s in.
By consolidating targets when you can not even reach the level to protect a single one you are making the situation worse, not better by consolidating. For it to make any real amount of sense they would first need to demonstrate an ability to prevent attacks at least in the correct order of magnitude and then demonstrate that they can scale up without creating correlated risk. Only then does it make any sense to actually centralize on a single solution, let alone a single provider.