Is presence of domestic SoC companies must to catalyst the growth of Design IP companies or Design IP companies can flourish where ever engineering talent is available in world? There are example for both the above cases. US, Western Europe, Korea, Japan and Taiwan are the example where presence of local SoC companies (who are basically the potential customer) fueled the growth of IP compaies in these region. But on the other hand Eastern Europe and India are the examples where there is virtually no SoC companies, but design IP companies are growing.
Perhaps the answer depends on the fact how much interaction is needed between IP vendor and customer at pre-sales as well as post sales stages and how much of those interaction can be done remotely (like via phone or e-mail). And also does this answer depends on the nature of IPs (like hard IP, soft IP etc) or it is independent to IP type.
Also another key points to observe may be is the role of sales and marketing team in IP business. Does the portal like design and reuse, chipestimate has reduced the necessity of cold calling from the IP sales force? These portals are becoming a market place where customer can get first level of information about the vendors of his requried IP and then he can send request to vendor for more information. If that is true then the role of sales team becomes more of technical support, contract negotiation, price negotiation. Easiness of doing these activities from remote location is higher compared to the knocking customers' door