They are rolling out the update now, the small stores will get it first which is expired to be complete this year, then the big stores will get it. That alone could take a year, only when every store has it will contactless be enabled.
In that year it gives customers plenty of opportunity to get in either direct contact with the CEO or tell Sainsbury's that you wish to pay via Apple pay. Not only that but you would expect both Samsung pay and Android pay to have launched over as well, this will just add to the demand for these payments systems. Ok it may take some stores a year or so to start accepting it, but in that year more and more stores will and there is a greater chance that by the time the stores who take their time to adapt to it do get on board then they will start off with limitless transactions.
Today the ball has started rolling here in the UK, it 's only a matter of time before pretty much everyone accepts it. Barclays have to rush out and do a deal with Apple due to demand, it won't take long for the remaining banks too as well. Look at the USA, real insecure banks are now enabling Apple pay, more and more retailers each day are signing up to it. That's going to start here as well.