I can't blame it on "cloud", though it's not helping that there are an awful lot of cloud services that claim to be "high performance" and are often mediumish at best. But in general I see a lot of ignorance in the developer community as to how fast things should be able to run, even in terms of reading local files and doing local manipulations with no "cloud" in sight.
Honestly, if I had to pin it on just one thing, I'd blame networking everything. Cloud would fit as a subset of that. Networking slows things down at the best of times, and the latency distribution can be a nightmare at the worst. Few developers think about the cost of using the network, and even fewer can think about it holistically (e.g., to avoid making 50 network transactions spread throughout the system when you could do it all in one transaction if you rearranged things).
Honestly, if I had to pin it on just one thing, I'd blame networking everything. Cloud would fit as a subset of that. Networking slows things down at the best of times, and the latency distribution can be a nightmare at the worst. Few developers think about the cost of using the network, and even fewer can think about it holistically (e.g., to avoid making 50 network transactions spread throughout the system when you could do it all in one transaction if you rearranged things).