I know people will just say this is a good thing but I should remind everybody that a software maker, even if they make the OS, should not dictate hardware use for it's users.
In other words I had a suspicion that their stubborn insistence on TPM 2.0 requirement and arbitrary cut off points for CPUs that could support TPM 2.0 with a header for no good reason was an attempt at basically helping out the hardware manufacturer partners Microsoft has but this bit of news? This is all but confirmation that is the case.
...and yet people are perfectly happy for Apple to go this route, or at least buy Macs with a T2 chip that pretty much prevents you from swapping out your boot drive, or being able to access that data on another device. Bit of a double standard isn't it, Apple can but Microsoft can't?
Based on current available options on Newegg, I can get a Hitachi 160GB storage HDD for $20. Or a 128GB TeamGroup m.2 drive (pci-e gen 3) for $24. And cheaper options exist if you consider options from brands that aren't common. Clearly OEM pricing may differ from Newegg but it's still a minimal cost, even at the budget end of the market.
I don't think pricing is an issue anymore. From experience the majority of users don't need 1TB storage on their local device, I've seen plenty of computers over the years that use 60-70GB of 1TB, so swapping out capacity for speed doesn't seem unreasonable.
On the cost saving measure, that's the reason some entry-level laptops that people complain about exist. Take the Surface Go Laptop - no-one on this website liked the entry-level option with 4GB RAM but when it's $150 per laptop cheaper than the mid-range option, that obviously becomes a decent saving over 10+ devices. But it's not an argument that holds up on HDD vs SSD based on current retail pricing. And in enterprise, even in the 3rd world, would prefer increased productivity that businesses will get from employees not having to wait 2-5mins for a computer to boot vs 10 seconds.