Not exactly.

The miles posted to a carrier's program can be used to book award flights on other *A carriers and for upgrades on many of those *A carriers. The later (upgrades)are only at the more expensive fares.

The first question is what do you plan to do with the miles? Miles are more "valuable / useful" when used on the same carrier as the program you are posting to. More space is generally available to the carrier program than that offered to partners.

Also, do you plan to seek status? If this is all you fly than that probably not an option.

On TK the award miles for discount business (J) book as 135% of miles flown (SFO-IST-BOM 9,722 miles x2 ). For UA that same TK flight with also earn 100% or if booked via UA 5 times fare (minus taxes) (estimate 17,000 plus miles). More expensive flight purchased vis UA tend to earn better with UA's approach, However a discount business it appears they will be roughly the same.--additionally you may not be able to purchase those flights via UA.
If purchased via TK, you earn a bit more crediting to TK

A useful generic discussion -- Which Frequent Flyer Program to Join? Help Is Here!