I've never understood this argument really. I think what the system may require is ever more debt or continual money creation (the same thing right?). I guess which may be linked to growth as without growth this may be inflationary? And which may be linked to growth because it creates a sink or swim environment where some are bound to default?The problem is that our economy has, since 1913, been set up to require growth because all the money in it is loaned into existence as interest bearing debt by the federal reserve. Without growth the holders of the debt have to default. A change to a steady state economy would require that the banks, who profit so extensively from the current system, be willing to allow a new system to be put in place. That isn't going to happen until the point when the current system collapses under its own weight.
Suppose a bank lends $100 out to the total economy (ok we're using ridiculous numbers for simplification purposes) and demands $10 in interest. Without overall economic growth there is no way to pay the $10 in interest back let's say. But WITH economic growth there's still no real way to pay it back seems to me. So with economic growth you have more widgets, the economy has far more houses or cars or something let's say. But there's still no more money. Only more money creation creates the $10 to pay back the loan.
Ok now don't all jump on me for oversimplifying economics (as it's way more complex than me ), I'm just saying I often interpret the argument that interest creates the need for growth as that growth itself will somehow create that which is needed to pay back the interest and I don't see how it possibly can. However I can see how a system in which there is not enough money to pay back the interest in total leads to dog eat dog competition among businesses to not be the ones left unable to pay their debt (because someone is bound to lose - zero sum) and this can create a need to "grow or die". However I am not really sure how this differs from the pressure from stockholders to "grow or die" as mentioned.
Btw: I have this book to recommend on alternative money systems. Money by Thomas H Greco Jr. (it has a forward by Vicki Robin). I especially like the description of mutual credit systems. It's the decentralized (and in many ways clearly libertarian) version (others call for public banking) However I do not think we should wait for alternative money systems to address environmental problems because addressing them is WAY too important for that, maybe at best something to be done in parallel.