Just because these pools dominate hashrate today, it doesn't mean they will do so forever.

As soon as market dynamics change, they could lose hashrate to other pools that provide more transparency.

In fact, block template is not the only issue with centralization on the mining industry nowadays. There's still lots of improvements to be made with regards to transparency and decentralization around share accounting and payout mechanisms. As soon as pools start implementing those (regardless of how small they are initially), other pools will be forced to follow.

SV2 doesn't really bring any innovation around these aspects however. That is still up to the pools to implement those.