> The primary benefit of 'Slack' over "older tools" is that the former are free – not just financially but in terms of how much time, effort, and energy is required to set them up and maintain them.
You are ignoring the costs that come from lock-in (inflated prices, lack of innovation) and migration in case the proprietary solution shuts down. That's the psychological tendency of humans that these companies exploit.
Lock-in is a cost of any solution tho. Whatever solution one picks, it's going to cost time and energy and, probably at least indirectly, money to migrate to another.
Non-proprietary solutions 'shut down' too, e.g. because the unpaid developers burn out and quit.
A lot of people reasonably believe that 'free' solutions are inherently riskier, all else being equal, because (generally) no one is being compensated to maintain and support it.
> Lock-in is a cost of any solution tho. Whatever solution one picks, it's going to cost time and energy and, probably at least indirectly, money to migrate to another.
That's not lock-in. Lock-in is when you are dependent on a (quasi-)monopoly, not just any potential migration cost.
> Non-proprietary solutions 'shut down' too, e.g. because the unpaid developers burn out and quit.
No, actually, they don't. The point, as above, is that it's not the sole decision of another party when a 'shut down' happens, that is, again, there is no monopoly. First of all, if you have free software running on your own machine, there is noone but you who can decide to just shut it down today, but also, in the long run, you can just take over maintenance of the software yourself, or you can buy/hire a software developer to do it for you, or you can get together with other users of the software to hire a developer.
Also, more generally, with regards to open interfaces/protocols rather than necessarily free software: No, email cannot be "shut down" because "the unpaid developers burn out". And changing my email client or server or hosting service does not necessitate everyone else I want to communicate with to do the same.
None of that guarantees that you can keep using things indefinitely at an arbitrarily low price, but that's besides the point: The price is determined by a market, and not by a (quasi-)monopoly.
> A lot of people reasonably believe that 'free' solutions are inherently riskier, all else being equal, because (generally) no one is being compensated to maintain and support it.
Well, yeah, those people are just clueless, if only because they confuse freedom with not paying for something. If you want to have something maintained, how about you pay for it? How does it make any sense to say that you prefer being forced to pay for something because you otherwise fear that it's not being maintained if you don't pay for it?
Also, none of this has anything to do with open protocols (which was the primary topic of this thread, kindof): Microsoft is being paid very well for maintaining Outlook and Exchange, which is both proprietary software. They still speak SMTP with the rest of the world, instead of forcing everyone to buy Outlook and Exchange to be able to communicate with their users.
You are ignoring the costs that come from lock-in (inflated prices, lack of innovation) and migration in case the proprietary solution shuts down. That's the psychological tendency of humans that these companies exploit.