aurynne - veggie 'bacon' (aka fakon 
) comes in long, narrow strips. Tastes a bit like Frazzles.
There's no reason why it couldn't be sold in squares, or discs. It does need to be thin because it's designed to be quickly fried, just to heat it through.
As far as I'm concerned, the main role of meat-like veggie foods is to make life easier when one family member doesn't eat meat, say - it's easy for a meat eating parent to cook (eg) pork chops with mash & vegetables, & just stick a couple of veggie bangers in a separate pan for that one person. Much less faff than when I was a vegetarian teenager in the 80s & had to make up burgers from TVP to cook alongside the family meal.
I cook nice vegetarian food from scratch for my family, & Quorn is seen as a convenience food, to be kept in so that dh can knock up burger, egg, chips & peas type meals for himself & the dc if I'm out. Occasionally I use vegetarian mince in a spag bol; I prefer to use aduki beans &/or lentils but the Frankenmince is quicker!
So, anyway, in answer to your question about why veggie food sometimes 'imitates meat' - basically, it imitates convenience foods & tends to come in familiar shapes/flavours because when people - often teens - decide to stop eating meat, they often start by looking for recognisable substitutions. Also, often the person deciding not to eat meat is not the person who does/pays for the family food shop, or does the cooking.
To reverse the situation, I have two dc who eat meat - I tend to buy things like pork sausages for them, rather than joints of beef - again, because sausages fit easily into the family meal that is already being prepared.