If true, BT will feel completely vindicated in the deal they did with Premiership Rugby back in 2013 that kicked off the crisis in European rugby (when Premiership Rugby sold them exclusive rights to European Rugby that weren't theirs to sell). The EPCR have indicated that they would be going with one broadcast partner this time round but it will really feel like the end of an era if Sky have really lost the rights.
There will also be uproar in Ireland where Virgin Media doesn't carry BT Sport, having fallen out with Eir last year.
I wonder if there may be a FTA highlights deal as a result of this, as the current two broadcaster for live coverage format lacks this. It might actually be easier for an FTA broadcaster to approach BT and the governing body, as it's only one broadcaster to deal with, wheras before it would require the agreement of both Sky and BT Sport.
Maybe there may also be a deal for some live coverage on FTA, and if so, look possibly to Channel 5, but don't rule out either the BBC or ITV.