Your AT89S52 chip needs a crystal, RESET circuit. All chips need decoupling capacitors.

Your 7-segment displays need current limiting resistors.

AFIK, Proteus will simulate a circuit regardless of 'no resistors'.
Do you intend to make this schematic in real life?

I have not followed this topic. It looks a nice simple way of driving the LEDs. You just shift in all 5 bit patterns whenever you want to alter the display. Uses 5 shift registers and lots of resistors, but simple software.

Another way is to multiplex all the segments, 8 segment resistors, one 'column driver' chip. Unfortunately an AT89S52 cannot sink very much current per pin. So you would need segment driver chip too (2 chips). Other MCUs have a greater current sink rating (1 chip). Or you use a purpose built LED driver chip like a MAX7219.

David.