The liberals leaders were never in power barring a short period in the 1980s, and eve then they were never really in power.
Without Deng himself China would have had moderate Maoist leaders after Hua purged Jiang Qing and the gang of four in 1976. The reform process would have started later down the road and probably at a slower pace. China today would be, at the 50th percentile, at where China was maybe 10-15 years ago. But if China ends up with weak leaders AND try to do reform Communism might have fallen whenever the Tienanmen square equivalent occurs.