According to Brian Bailey
The other problem for the EDA companies — and this has been a consistent problem with SystemC — is that there are reference implementations. This makes it a lot more difficult for an EDA company to provide the necessary investment and to get a return from it. The market expects a price of zero and that means no incentive for the EDA companies to provide support.
Now as to open-source and EDA investment – I think the state of the industry speaks for itself. Yes – they have integrated SystemC, but they do not put the same dollars into – as an example – optimizing its execution as they do for Verilog/VHDL.