That sort of advice is far too generic to be useful.
I wouldn't say that. Those three alone can make a huge difference when it comes to page loading times.
If a provider is using SATA, SAS, or even SSD Disk IO can be a bottleneck. NVMe has much higher disk IO/IOPs available and providing the provider offers generous LVE limits from CloudLinux then there could be a significant difference with page load times for the customer.
If a provider is using Apache, they aren't able to handle as many concurrent connections as good as a provider who uses LiteSpeed Web Server.
Even using LSAPI from CloudLinux has an advantage over using Apache Web Server.
But the best way to go about it is to use the full LiteSpeed Web Server version. Then the provider can offer LSCache (part of LiteSpeed) for WordPress, and each customer can use LSCache plugin at no additional cost to optimise their websites.
This saves the customer having to spend money on 3rd party plugins like WPRocket or similar, which aren't as good as the full version of LSCache.
LSCache also has Image Optimisation, so no need for the customer to pay for additional plugins like Smush or similar plugins. The more plugins a customer uses, the more it uses resources from the customers' account, which can cause resource/slowness issues for their account and websites.
I've seen lots of customers try to use security/optimisation plugins which aren't even that good and slow their account/site down.
I use Imunify360/LiteSpeed, and as they run at the server level i.e, it doesn't use resources on customers account. Optimisation/Security is done at the server-level and using resources as root, not using the customers' resources that have been allocated to them via CloudLinux LVE manager.
You will notice some providers offer less expensive hosting when LiteSpeed is not being used but charge more for different plans that do include LiteSpeed.
Coming back to CloudLinux LVE manager also plays a big part. Majority of providers running cPanel/DA use CloudLinux and the LVE manager which is used to offer better stability for the server which is done by restricting resources to each customer so no one website/account can cause the server to crash.
Some providers offer better CloudLinux LVE limits than others. Generally, the more resources available within LVE, the quicker CMS will run. But it isn't all just about LVE limits.
There is a lot to it, and I could write ten pages of this stuff.
But as I said, CloudLinux, Imunify360 and LiteSpeed play a big part in how slow or fast websites load, along with the type of storage used to serve content for the websites too. NVMe is newer and faster.