Of course they can. Can Celtic thrive without them? That's a much more contentious question.
So before Hoops fans gorge themselves senseless on jelly and ice cream as Rangers prepare to go into liquidation, they should digest this simple fact of life.
Celtic are a stronger entity with Rangers as their competition. That's as true in terms of football results as it is financial results.
Which is why, when it comes to voting on a newco Rangers retaining their place in the SPL, much as it might stick in the craw of Celtic fans, they have to accept they must come to the aid of their arch rivals.
Without Rangers' presence, the 11-1 voting structure on which Celtic rely to maintain their joint grip on the most important elements of the SPL will be lost.
The cost to the Parkhead club would come in terms of their share of TV revenues, which themselves would be in serious jeopardy of diminishing substantially with Sky certain to view an SPL without Old Firm games as a product they would struggle to sell to subscribers.
Likewise, sponsorship income would be in peril as the sole attraction for anyone prepared to put cash into Scottish football is the prospect of exposure which the big two bring.
More immediately, the sale of season tickets would suffer, given that so many Hoops fans renew them simply to ensure they get a seat for sell-out Old Firm matches.
Sure, a Rangers-less SPL would open the door to a period of championship domination by Celtic, which would satisfy some, for a short time, at least.
And, with only one Champions League spot up for grabs for the foreseeable future after next season due to Scotland's falling co-efficient, the prospect of being confident of finishing as SPL champions and thus booking that place would provide some sort of comfort blanket for the Celtic money men.
But it is only by reaching the group stage that the pot of £12milllion-plus can be grabbed.
If the level of competition faced on a weekly basis falls, as the departure of Rangers from the scene is reasonably expected to cause to happen, would it help prepare Celtic for the challenge stepping up to the Champions League level already represents?
Without the carrot of Champions League football for the past few seasons, it has proved increasingly difficult to attract established, quality players to Parkhead.
Remove Old Firm games from the limited highlights package currently on offer –and for all it is criticised, it remains a spectacle held in some esteem abroad – and joining Celtic will become an even harder sell.
The repercussions of losing a club of Rangers' stature – especially in the circumstances in which they have plotted their own demise – is also sure to have a negative effect on the already damaged image of Scottish football.
Would Celtic be in a position to increase the wages on offer or the transfer budget available to the manager to counteract this damaging fallout from Rangers' liquidation and removal from the SPL?
That's highly unlikely, given how their own income would be negatively effected.
Of course, chief executive Peter Lawwell and the Celtic powerbrokers could see this as the opportunity to pursue their long-held dream of moving to a more lucrative and rewarding league.
But the major obstacles remain, so that's an ambition they can't take to the bank. Supporting the retention of some form of Rangers in the SPL remains a sounder investment.