Note that we're not backed by a a venture capital firm that needs a 10X exit, we're self-funded and have been sustainably growing ~50%/year since we got started. We're over 100 people so paying for 2 developers on Roundcube (tripling the resources being put into Roundcube today) would be trivial for us.
We'll look what users want, what's best for the ecosystem etc, but we're not looking to kill it and if we ever would, it won't be for the money.