You may lose a sponsor, but you make up for it on shirt sales.
How?
Casuals aren't buying $100+ jumpers.
From another perspective would you want Brighton to remove names from their player shirts and plonk another sponsor on there? You do see it in other sports where casuals will purchase a name/number top of their favourite player, heck I saw a Man United Tevez 32 top this year from someone still wearing one.
I wouldn't care less if they did. I know who all the players are.
Most of those casuals buy fake knock offs anyway so the club makes sod all money from them. These causal fans actually ruin clubs social media platforms with their s**t.
Again you are taking it from a die hards perspective on a dedicated footy forum, it's the every day man that putting names on jumpers is geared towards. You aren't the target audience.
And you're pandering to a very small amount of people who will overwhelmingly not buy a clubs jumper at the price they are.
You're basing your view on a market that hardly exists.