when he started, he didn't have heat stable polymerases- that came later. Instead you had to add more pol each step, which was a huge pain.
I know, just glad I worked in a molecular biology lab after Taq was discovered. My lab experience was akin to his first hopes — put the reagents in, place it in the thermocycler, and pick it up the next morning.
you probably worked in a lab during the period where scientists, annoyed that PCR machines required purchase of licensed Taq, simply cloned and expressed their own and used it instead.
If only I were so lucky, might've made me more thoughtful when planning experiments