The problem is not paying an inflated renewal fee, something that most end users still wouldn't understand, because a .com costs roughly $10 at nodaddy, and most people think that no domain should be worth more than that. The problem is when there is no price control, and the registry can jack up the price at will, possibly price you out, making the foundations of your business shaky.
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Price shifts in the real world happen all the time - the price of oil, the price of fertilizer, the price of advertising, the price of employees, the price of beer and pajamas for those that work at home.
That said - the rules are that renewals have to be consistent so they cannot simply jack the price up to any that they want unless they do it for ALL registrants with sufficient notice. The premium renewal is an exception because the registrant explicitly accepted those terms at registration. This idea that you can have a domain that suddenly goes from $10 to $1000 dollars is largely flawed and not allowed as that would be the renewal to ALL their registrants. The net loss > net gain so it won't happen.
Furthermore, the .com contract is changing 2018 and price increases will mostly be allowed. There's no point to the premium structure when those names are gone... you can't expect an increase from $8 to $100 because the lost registrations would be enormous.. however, if you knew you could raise prices 20% to about $10 on 100 million names+ and it results only in a 10 million drops you'd think about it too.
ALSO any initial reg can be done for up to 10 years so pretty much no shift there
The "moving sands" is quite misleading. Most domainers are worried about something like a shift from $10 to $100 but that's because their inventory cost grows considerably. A business with 2-3 names doesn't care nearly as much. People with 30,000 names might not be amused

{It will happen, imho}
It's a great com is king argument though, isn't it.
The one true issue for domainers that exists already is more around registrar rebates and discounts that aren't renewed. This is an issue for the .TV crowd where you see 10.99 specials that disappear.
