Old tunes are PROHIBITED. It's too Castlevania like.
We need to be generic and average, to draw in the casual crowd.
That's a fairly immature approach.
Be realistic: what's the odds that a new developer from another continent either was allowed to use some else's work in their game as they saw fit? Or that a composer would sit down with a "dude, we know you're good but we don't care, just remix us this stuff"?
They probably sit down and made a short list of songs that could be kept as "cameos" (ended up being 3 or 4) and then the new composer was allowed to do his job. A more respectful approach for him and also for the composer who came before and whose work wasn't "stolen" by some dude from Spain because some wig said so.
To make an example, if tomorrow Supermegawesome JRPG of Doom I comes out, and it sports Sakimoto's soundtrack, and then they do II and III, and then Sakimoto retires, when it's time to work on IV they'll need to get another guy to work on it. And said guy will have to do new music, as remixing Sakimoto's work would be humiliating for him and unfair for Sakimoto.
If LoS was an in-house product, it would have made a lot of sense to have the same tunes and more continuity. But outsourced to a spanish team?
I understand it's a pain because A) the traditional CV music is definitely catchier and has more personality and B) some of the remixes (Waterfall/Courtyard) are so bloody amazing that I can only wonder what they could have done with Simon's Theme and Bloody Tears; but I wouldn't read too much into this. They probably had no choice at all for this aspect.