OP: top schools have admitted transfers from community colleges – but only in very unique circumstances. These students weren’t kids who “got their act together” once they reached comm college – they were students who as seniors, applied and were accepted at a good no. of very selective colleges but for some reason, could not attend and ended up at comm college. These were kids who, as seniors, were accepted by Dukes, Stanfords, Haverfords and Browns and had the HS transcript, test scores and achievements that got them accepted.
The “late bloomer” who becomes a 4.0 GPA at community college with an indistinct HS record has, frankly, no chance to transfer into these extremely selective programs (unless he/she was an extremely important athlete).