It was a good weekend for Nottingham Forest, although perhaps not as good as it looked like it might be on Friday night. That evening, when they handed Sunderland their record defeat at the Stadium of Light, winning 5-0, Forest must have been expecting to pull away from at least one of their relegation rivals. As it turned out, though, they ended the weekend where they began, five points clear of third-bottom Tottenham and three clear of West Ham with four games remaining after both the London strugglers also won.

It was a classic Saturday afternoon in the relegation battle, the sort that is rare these days with games so spread out over a weekend. But Tottenham’s match at Wolves and West Ham against Everton kicked off at the same time, which meant that Tomáš Souček’s goal for the Hammers six minutes after half-time not only prompted celebration at the London Stadium but also anxiety among the Spurs fans who had travelled to Molineux. Then João Palhinha put Tottenham ahead with eight minutes remaining and Kiernan Dewsbury-Hall levelled for Everton with two minutes to go. Had it stayed like that, Tottenham would have been out of the relegation zone on goal difference. But Callum Wilson scored for West Ham two minutes into injury-time, lifting them back above Spurs and within three points of Forest.

In that sense, nothing changed at the bottom, except that Leeds, unbeaten in six in the league, who may have thought a run like that would have dragged them to guaranteed safety, are only a point above Forest. Newcastle, who lost their fourth successive league game at Arsenal are only two points above that. Even Crystal Palace and Sunderland, one point and four points further clear respectively, are not mathematically safe. Realistically, it’s unlikely that Spurs, after 116 days without a league victory before Saturday, are suddenly about to win the three out of their last four games they would need to bring Palace into play but, equally, it seems very plausible that 40 points, the traditional threshold for presumed safety, may not be enough this season.

Only three sides in Premier League history have ever been relegated having amassed at least 40 points: Sunderland in 1996-97 and Bolton in 1997-98 – both got 40, while West Ham managed 42 in 2002-03. The contrast with the past two seasons when the team third from bottom picked up 26 then 25 points is striking. Not since 2015-16 when Newcastle went down with 37 points has a side with more than 34 been relegated. So what’s changed?

It’s entirely possible this season could be an exception. It’s possible as well that Tottenham lose their four remaining games and go down with 34; although they have shown more fight under Roberto De Zerbi, confidence remains low and their injury problems have been compounded by Xavi Simons suffering a ruptured ACL against Wolves.

The biggest change, though, has been the performance of the promoted sides. Last season they got 59 points between them, the season before 66. This season, they have already amassed 106. While Burnley have struggled, Leeds and Sunderland spent significantly and well on players. It’s unlikely that Coventry and whichever two of Ipswich, Millwall, Middlesbrough, Southampton, Wrexham, Hull and Derby come up with them will match that level of expenditure. Though it is possible, as Ipswich and Southampton have recent Premier League experience and Wrexham have their Hollywood backing.

More generally, this has been the best season for the Premier League’s middle classes since that 2015-16 season, when Leicester won the league, Southampton came sixth and West Ham seventh. The following summer saw a wave of spending from the traditional giants and the brief bout of equality was swept away. The Premier League’s Profit and Sustainability Rules (PSRs) have a bad reputation, thanks in part to aspirant clubs with wealthy owners who feel they prevent the sort of investment that might allow them to reach the next tier of clubs, but this perhaps is a sign of the system working, evidence of how incremental improvement and sensible husbandry can make even a relatively modest side competitive without richer clubs just surging away. PSRs, though, will be replaced next season by Squad Cost Ratio, which appears to allow those with deep pockets to exercise their advantage more thoroughly.

For now, though, the Premier League has been left not only with a proper title race but also with a true battle against the drop. This is how it ought to be, with every matchday bringing multiple dramatic twists and each of the four sides likeliest to occupy that third relegation slot having unexpectedly found at least some late-season form. And that has one or two other sides beginning to feel a little uneasy.

• This is an extract from Soccer with Jonathan Wilson, a weekly look from the Guardian US at the game in Europe and beyond. Subscribe for free here. Have a question for Jonathan? Email soccerwithjw@theguardian.com, and he’ll answer the best in a future edition