Pre 2000s. The might of lower league sides like Logrones, Albacete or Compostela. Hell, even Atleti and Sevilla used to get relegated back then! Point is, fans don't realise how far La Liga teams have come in the last 2 years compared to the years prior where top 2 were 20 points ahead of the rest of the pack. In peak Ronaldo-Messi era Granadas and Almerias used to get dispatched just as easily with both teams on +63 goal difference. Now there is no defined top8. Something like 13 points between European spots and relegation with 14 games left to play. Everyone can beat everyone these days at home.
TBH look at how similar situation is for France right now to what it was when Perez took over RM. Big personal project pump to boost the rebirth of a seemingly downtrodden giant that ultimately helped make La Liga the top2 league in world football. A Spanish FA marketing project that was not sustained from 2008 onwards on TV rights side of things and ultimately lost the battle to the English due to cultural differences.
Monaco, Lyon and Marseille as the other esteemed homegrowing grounds (which aren't even exclusive since Paris is doing a good job cultivating their own guys), lots of teams seesawing in and out of European spots including Nice, St Etienne, Reims, Rennes, Montpellier, Bordeaux... same thing used to happen in Spain in early 2000s where piss poor sides had absolutely no hope to grow, but there was an established rotation of top8 clubs like Depor, Zaragoza, Mallorca, Bilbao, RSSS, Villarreal from Pellegrini era..
France sure seems to be on the right track and is one investment away from being the new La Liga of the noughties in their own way. Talent pool is already there, just like there was for Barcelona post-Gaspart. But in today's world, someone will need to help them out to have true title competition. Doesn't mean the rivalries will be revered by fanbases abroad as they were in the case of English or Spanish teams, but for sure, the rest of the league will benefit from having a team with serious European ambitions. And they already have at least 2 sides that go out to compete without fear.