It's called brand identity. Every major manufacturer makes vehicles that have similar styling cues. It's only really Land Rover that historically hasn't, due in part to perpetuating old designs and changing ownership multiple times.
The simple fact is that you just can't build a new car anymore that is technologically still in the 1950s- with big lumps of steel on the front, external door hinges and entirely manual mirrors. No one will buy it, and more and more markets won't let you sell it.
My personal opinion is that the production of the 90/110 should have ended when the discovery was launched, and that branded as its replacement, with a few extensions to the range.