@resistion- this is obviously pretty specialized stuff. It may seem like the number of foundry players is increasing, but it's not necessarily so.
I bounced your question off Bill McClean of IC Insights. He said:
"There is an occasional startup in pure-play and IDM foundries but it is offset by pure-play mergers (e.g., HHNEC and Grace, GF and Chartered, etc.) and IDMs exiting the foundry business. Overall, I don't think the total number of companies involved in foundry is changing much."
IC Insights tracks more than 20 pure play foundries and at least 26 IDMs that do some foundry work.