Do you suggest that Dickens wrote good books in bad style, while Bulwer wrote just bad books. I'll answer with another citation, from Mencken.
"England has the best second-raters in the world; nowhere else is the general level of novel writing so high; nowhere else is there a corps of journeyman novelists comparable to Wells, Bennett, Benson, Walpole, Beresford, George, Galsworthy, Hichens, De Morgan, Miss Sinclair, Hewlett and company. They have a prodigious facility; they know how to write; even the least of them is, at all events, a more competent artisan than, say, Dickens, or Bulwer-Lytton, or Sienkiewicz, or Zola. But the literary _grande passion_ is simply not in them. They get nowhere with their suave and interminable volumes. Their view of the world and its wonders is narrow and superficial. They are, at bottom, no more than clever mechanicians."
--H. L. MENCKEN, A BOOK OF PREFACES (1917)
In 1917 Mencken placed Bulwer-Lytton in the same rank as Dickens and Zola, and above Wells and Galsworthy. Interesting, isn't it?