LD's were bulky and heavy.

Yeah, inconvenient.

LD's were very expensive - around USD50,00 for a movie.

No. they were cheaper than their VHS counterparts on average.

LD's were dual sided, with only 60 mn max per side.

Yeah, inconvenient.

LD's weren't very reliable. Laser rot anyone?
And so on...

They were more reliable than VHS cassettes. Laser rot fortunately was fixed.
Ultimately the problem with laser discs were mostly a matter of convenience.