If you split your money 3 ways you have 3 chances at success and end up with 3 IPs at the end of it. Spending all your money on one show puts all your eggs in one basket.

Plus it is in generally cheaper in the UK and elsewhere in the world to produce shows than it is in Hollywood/US. So it is not the same comparing a 10 episode US show to a 10 episode UK show monetarily anyway. Like I said, US productions have crazy money at their disposal, not so elsewhere.