With one match remaining of the 2016-17 campaign, sixth-placed Manchester United are 20 points ahead of Southampton in eighth, with the Baggies trailing Saints by one.
The West Brom boss believes that the leading clubs will spend more money than ever during pre-season, as the race to qualify for the Champions League becomes ever more competitive.
Pulis told Sky Sports News: "I think all the top sides have got stronger in the summer and they have really taken everything by the scruff of the neck in respect of playing the so-called smaller teams.
"I would really like to see the points the top clubs have taken off the so-called lower clubs this year compared to last year - and I'll do it when the season has finished.
"I'm convinced, because the top four is getting really competitive, that the top six or seven will spend enormous amounts of money next year to enable them to get in the top four. I'm convinced that's what will happen and I think they will push on."
West Brom wrap up their Premier League season on Sunday at Swansea City.