We detached this subthread from https://news.ycombinator.com/item?id=11780119 and marked it off-topic.

You've mentioned Bitrix24 in 2 of your 3 posts on HN, either you're a fan and passionately advocate this product...

...Or you're not disclosing a interest in the company.

Since when is a run-of-the-mill cloud PBX a "Twilio alternative"?

There have always been competitors in this space. There used to be bunch of companies, and there are still several, that offered various levels of telephony integration, especially in the SMS/MMS space. I kind of view Twilio as the Stripe of the telephony world. Twilio came along and made a developer-friendly API around a bundle of services, where before you may have to use one service for one thing and another for something else. Or one provider may only reach some carriers and not others. Twilio kept it basic, not really building anything on top of their API, just selling the API itself. Other companies tried to compete against their own clients. For example, many SMS/MMS providers would offer an API, but then compete against their clients by also selling campaign management platforms or mobile marketing services.

The commercial SMS market is full of companies that are rivals but also customers.

This is happening because the actual network operators often require their customers to provide a volume of X SMS's per month, and they have to pay upfront. They are then selling their capacity downstream in a long distribution chain, finally ending up with regular businesses that wants to add SMS capability.

Regulation changes is the only thing that stirs the market tbh.