Dedicated servers offer the best performance, especially on a per-dollar basis. Most cloud vendors give you more storage, not faster storage. If your operations are relatively simple, a single dedicated server with RAID 10 will usually out perform more costly and complex cloud offerings
Cloud makes these migrations easy, but a dedicated servers avoid the need of migrations. With a dedicated server, we can easily check the hardware and rule out issues.
With cloud computing, the compute node is usually just a commodity server minus the storage. If that node dies, so does your workloads. This is not much different than a CPU, RAM or power supply failure on a dedicated server.
Cloud infrastructure, especially with AWS, adds layers of complexity that you may not need. With AWS, your IP addresses are not automatically bound to any specific EC2 instance. If you stop and start that instance, you must remember to re-associate your IP address.
When you examine the technical requirements needed to ensure reliable performance for your sites, you will often find that dedicated servers give you the best value for money
Many cloud vendors, if you begin to integrate more complex services, you may find you are locked into their solutions. This can be dangerous if their support, services or pricing changes.
In Cloud you can increase your CPU/RAM or add a database, but you already have these options with dedicated servers. Cloud just makes it easier.
There is no single point of hardware failure in cloud computing. The odds are in your favor that there will not be a catastrophic data loss in your storage, though it has happened.