The Parkhead club look almost certain to win their seventh title in a row this season as they hold a ten-point lead with a game in hand.
Rangers have managed to get closer than they did last term, when they finished 39 points adrift, though Warburton believes the gap has been narrowed by Celtic regressing rather than the Light Blues improving.
In order to finally overtake Brendan Rodgers’ side and stop them from winning ten-in-a-row, Warburton believes both investment and patience will be required.
He told Sky Sports: “You have to recognise that Celtic have been in the Champions League for the past few years and done well to get to the group stage and with that comes the financial rewards and all that does is increase the gap between Celtic and Rangers and every year you’re fighting to close that financial gap.
“The longer Celtic are exposed to Champions League football the greatest the financial divide becomes so Rangers need the investment and they need to dampen expectation and recognise you’ve got to build the club back up because it is an outstanding club, it’s a football institution and it was a privilege to manage up there.
“But you’ve got to be patient with it. Be honest with the fans and give them clear communications as they aspire to get the club back to the top of Scottish football but it will take time and it will certainly take investment.”