"However SAP and Oracle are the leaders. The others were bought by Oracle or SSA so not much future to expect for those products."
This is not quite true. Oracle launched the Apps Unlimited program, promising unlimeted evolution of the PeopleSoft, Siebel, and JD Edwards product lines. In HR for example PeopleSoft has been the world leader for some time. They can not force customers to go and use the Oracle e-Business Suite because customers are not willing to go there. So PeopleSoft is here to stay (and especcially in HR). For CRM they will focus primarily on the Siebel product (not on their own, nor on the PeopleSoft, or JD Edwards CRM product). So Siebel is here to stay. For JD Edwards the future might be less sure. Oracle will not sell JD Edwards licenses directly anymore. They leave that up to the partners. But the Apps Unlimited program also has JD Edwards in scope, so it looks like they will keep on developing there too.
Why do they do this??? Because they want to keep the customers!!