One Strong Tower Or Five Weak Ones - It Depends On The Map
Both approaches show up constantly in the genre, but the risk they carry is almost opposite. Worth knowing which one fits the map you're actually playing.
One strong tower: efficient, fragile
A maxed-out tower covering a chokepoint can carry an entire map, but losing that one tile to a bad placement or a stray leak costs the whole investment at once.
Many weak towers: resilient, slower to scale
Spreading gold across several cheap towers means no single loss is catastrophic, but early waves take longer to clear while income is still building up.
The honest answer
Short maps favor one strong tower - there's no time for spread coverage to pay off. Longer maps favor several weaker towers that scale with your economy. Most Novayug titles reward knowing which map you're on before committing to either.