Lyon being bad is definitely something historically sad. I watched them dominate this league when I was growing up, during my college years Lyon was the best team and they had some great European games as well not just France, and unfortunately financial ruin caused them to never recover.
I feel like they need to do better though, they have income, and they are spending way too much on player salaries, if they could get younger players for cheaper, then about a 50-60 million salary spending would be possible and they could pay that easily and then get out of debt. Sell some stuff that they own too, whatever they can, it would cover some of the debt, just like how Barcelona sold some stuff to pay the debt and get some players.
I think Lyon needs a revolution and they need a shock to get the team improved again. Maybe they should have a better manager because having a new coach couldn't help this team at all and even spending too much money for hiring new players couldn't help them too.
Now Lyon is again in danger and if they continue this bad performance during this season, we can expect to see Lyon getting relegated which is the worst ever thing for Lyon. As you said Lyon was one of the best teams in France but they should find the weakness as soon as possible before they lose more time.