To be fair, I’d imagine they probably could. Especially since the Splash Canyon incident, I’d guess that Thomas Land visitors provide the vast majority of Drayton Manor’s guest figures; where I live in the South West, pretty much everyone I know who’s been to Drayton Manor went primarily to visit Thomas Land. As much as I think that moving primarily to being Thomas Land & the zoo would create a less varied park, it would be a solid move if they wanted to ensure their longevity post-COVID, as the park’s recent financial struggles even pre-COVID were quite well known, and the extended closure combined with the floods may have made these worse.
As much as I did like Shockwave and Apocalypse, I don’t think they (the thrill rides) are really what pulls people to the park anymore. So if they do remove these as part of a progressive move towards being a family-orientated theme park, then I think it would be a solid move to make if they were really struggling. Especially if they have more future success down the line and replace them with attractions more suited to their new target audience.