If two clubs merge, and play at the ground of one of the clubs, then the other club dies. That's reality.
For instance, if all the clubs in West Yorkshire merged and played at Headingley, it wouldn't be long before they became known as the Yorkshire Rhino's, shortly followed by being called the Leeds Rhino's (I'm not picking on Leeds here, just an example). A quick way of killing off a lot of traditional clubs, and decimating the (already small) numbers that do turn out week in week out to support their team.
FFS, just invest in what we've got and spend some of the millions in Sky money we have in attracting and developing our own home grown players. Properly run academy and reserve leagues would be a great start.