New crown vs. extraction and implant? (Photo)

I had a loose crown on tooth #30 The dentist pulled it off (wasn’t easy) And said “tooth is done “ I was so confused. This is a root canal tooth that had a crown. He said not enough tooth left to crown. “Should get extraction and implant nothing lasts forever” I got a 2nd opinion and was told I couid do a tooth build up with post/pins if necessary and crown the tooth I’m so confused as what to do? I want to save it and do a crown but will it last? will bacteria have gotten in there