I understand and appreciate the skepticism, however, the reason we're making this change is because we want to provide the best experience for our users.
Pinterest receives value from the ongoing operation of Instapaper in the form of continued parsing improvements and aggregate information about links on the web, and that value is enough to justify our relatively small operating costs.
For me one part of "growing up" in sw engineering has been that I have started to want to pay reasonable amounts for things I use actively.
I see it as an insurance for us users: as long as a significant amount of users are paying keeping the service as-is is a valid alternative for the owners.
When it becomes free I fear that someone suddenly starts looking at it as a cost center, I mean: all the benefits you mention seems to be possible without operating an end-user service.
Disclaimer: not a paying Instapaper customer, but I am a paying lastpass customer and a paying google docs customer etc etc.
I don't have a statistical survey, but I have anecdotal evidence of paid services going away, increasing in price dramatically, or remaining the same. Same with free services.
I can't honestly say that the paid-for services I use are more likely to remain available than my non-paid services.
The key factor appears to be a viable business model, but that's impossible to evaluate from the outside (and sometimes from the inside).
Would you mind elaborating on how Pinterest derives value from your "aggregate information about links on the web"? What types of data do you/they glean through Instapaper?
That's quite interesting, are you using Instapaper to allow you to get more expansive testing on the parsing technology before rolling in the main product or are they reasonably lockstep?
How I wish Pinterest saw some value in keeping Fleksy - the keyboard app they acquired, updated. It is/was one of the best 3rd party keyboards out there, but has gotten buggy with newer iOS.
Pinterest receives value from the ongoing operation of Instapaper in the form of continued parsing improvements and aggregate information about links on the web, and that value is enough to justify our relatively small operating costs.