Detroit's trajectory is looking a lot like the Flores Dolphins IMO. Year 1 was a feel-good tank for both teams. They tore down the roster and put a terrible team on the field, but at least that team tried to win. They played harder than they had in a while.
Year 2 and 3 for Flores were about spending his mountain of cap space and draft picks to bring in talent, and turn a scrapper into a contender. But it was only a partial success. He built one of the best defenses in the league, but his offense was undermined by a horrible OL and a QB that may just not have it. Flores thought that Tua wasn't the answer, and that seems to have been the reason for his bitter split with Stephen Ross.
Dan Campbell now faces a similar fork in the road as Flores did in Year 2. He's got a team that plays hard for him, and he's going to have a lot of money and draft picks to build a team his way. The Lions will live or die on how well he spends that cap space and who he chooses to replace Jared Goff next year.
I don't think Detroit will be ready to contend this year, but they should at least leave the 2-win cellar. After that, they face a huge decision about their next franchise QB.