The classic answer is that chambers are more limited to office sharing and only provide clerks. But this is clearly not the case as chambers often provide websites as well with getaways allowing one to peruse the different barristers along with their specialties to select and contact the one most suitable to represent one in one’s case.
There’s also the whole pupillage system so it’s clearly not limited to “just clerks and office space”.
Chambers are based upon an "eat what you kill" principle, in which each barrister's compensation is based predominantly on the work performed by the barrister personally.
In contrast, in a law firm, partners share profits to some extent with each other, both from their own work, and also by buying the work of paralegals, associate attorneys and non-equity partners "wholesale" and selling it to clients at "retail". Law firm partners make a significant share of their income from the efforts of others and typically have to do their own business development and retention agreement negotiation rather than having this done for them by clerks.
Likewise, law firms have more control over their client base than chambers in which the member barristers do not have full control over whom they represent and are not actively involved in marketing their own services. Medium and large sized law firms typically evolve from representation of a small number of clients with a high volume of work at their core.
Lawyers in law firms are also at much greater liberty to work together in groups on cases or for an overall legal strategy for clients than barristers.
