What doctrinal lessons have the IDF learned that leads them to field heavy 60t+ APCs like Namer, rather than the 30-40t APCs by everybody else? And why aren’t other militaries following suit?

Is it basically survivability vs mobility?

If so, it seems that other western militaries quite like high survivability too…

Secondary question… why have there been very few medium-weight vehicles in the IDF? Their line up looks to be MBTs and HMMVVs, save for lighter M113s…