If they lose half their customers, the 3.5% fee won't matter, they will go out of business.
And if they lose money on most of their customers they go out of business.
In the end take up with the card companies. Why the hell are they charging 3% of EVERY SINGLE TRANSACTION over and above their network fees to move around a bunch of 1s and 0s which happens for them functionally free. It’s not like the old days of credit slips. Also note if you pay by DEBIT card instead of credit card, no fee. And these debit cards run under the exact system, they’re just moving their 1s and 0s around different buckets. So how can they run my Visa debit card for free but my other Visa backed credit card charges the store 3%, plus of course charges me interest.
The system as it currently operates is a scam run by the card companies. Has been for decades. We the end customer are only just now finding out about it because the stores are finally putting the scam on the receipt.
So if you really really think this is a bad thing call your card company, tell them their business practices are abusive and they should stop #$%&ing the stores.