LMAO are you for real? There's nothing "in it" for small/boutique firms. People go there if they can't go to the big firm of their choice. That's like asking why people prefer to work in Bharat Bank as opposed to Barclays or Deutsche Bank.

I suppose piss poor pay may be ameliorated by better hours and better "mentorship" if the stars align, but wouldn't count on it. small firm associates are just as likely to be overworked and exploited by toxic bosses lol