[hvasilev]

That is a hard theory to sell, since it happens only in places where the FOSS has established dominance and (for example) the state of the top contender is horrible. There is simply no economic incentive to pursue a better debugger.

[AstralStorm]

Yet Microsoft does so in Visual Studio, and apps like IDA Pro exist and are quite expensive. And there's a whole lot of proprietary ARM debugging platforms.

Even in FOSS there is also lldb and edb. (And gdb can be made more palatable by a front end such as ddd.)