Combine 2 PublishSubject's and emit with Observable.combineLatest

I have 2 separate collections of data in my service.

Featured and Standard content.

I have 2 api's calls I make to return these items. They can be consumed separately, however I also have use case when I would like to take both sets of data, provide some enrichment based on a condition and then return them to a consumer.

I was hoping I could do something like this:

class ContentService: ContentServiceType {

    let featured = PublishSubject<[Content]>()
    let standard = PublishSubject<[Content]>()

    let content: Observable<(featured: [Content], standard: [Content])>

    private let client: Client<ContentAPI>
    private let disposeBag = DisposeBag()

    init(client: Client<ContentAPI>) {
        self.client = client

        content = Observable
            .combineLatest(featured, standard)
            .map { (featured, standard) -> (featured: [Content], standard: [Content]) in

        /*
            Do some enrichment and create then return new, updated versions
        */

                return (featured: updatedFeatured, standard: updatedStandard)
        }.share()
    }

    func fetchStandardContent(page: Int = 0, size: Int = 100) -> Single<Void> {

        let params = ["page": page, "size": size]
        let request: Single<Content> = client.request(.getStandardContent(params))

        return request.map { [unowned self] launchers in
            self.standard.onNext(content.props)
            return ()
        }
    }

    func fetchFeaturedContent(page: Int = 0, size: Int = 100) -> Single<Void> {

        let params = ["page": page, "size": size]
        let request: Single<Content> = client.request(.getFeaturedContent(params))

        return request.map { [unowned self] content in
            self.featured.onNext(content.props)
            return ()
        }
    }
 }   

Elsewhere in my apps I was then hoping I could do something like

        contentSvc.content
            .observeOn(MainScheduler.instance)
            .subscribeOn(ConcurrentDispatchQueueScheduler(qos: .background))
            .subscribe(onNext: { content in
               /* do something w/ content */
            }).disposed(by: disposeBag)

And then whenever contentSvc.fetchFeaturedContent or contentSvc.fetchStandardContent is called, the contentSvc.content subscriber above gets new data.

Instead content does not appear to be emitting any values.

combineLatest requires both sources to emit before it will emit itself I believe.

I would perhaps look at using a BehaviorSubject or BehaviorRelay instead of a PublishSubject.