No incentive to do that. It’s more than good enough for the type of trading their customers do. They have no interest attracting HFT type of traders. I wouldn’t be surprised if they shut it down, which would be a real shame.
Well, only they know the traffic through the api and whether it's worth maintaining it. My hunch is there is quite a share that goes through the api. Perhaps you are right re limited desire to invest in a revamp. Perhaps their commission model and quality of api are in sync? To take significant marketshare of algo trading from competitors it's not good enough to offer a top rated interface but the commission structure would have to be equally competitive. But it's not for higher frequencies with high daily turnover.
I have never used IB to stream data because they make it very clear that they are not a data provider. They provide data for their platform. They also provide data via the API as a convenience. The API for trading is quite good, robust, and works very well. Their platform does a lot, but I suspect that most traders find a trading platform that more closely matches their needs. If you seriously want to do trading through the API, and the data streamed from IB does not meet your needs, you may want to look for a data supplier that does. I use DTN IQFeed but, in the good value category (compared to the others I have looked at) you may want to consider Polygon.io also. There may, of course, be others. Also, I only trade stocks so... Alpaca Hmmm. Just looked at the website. I don't think this would appeal to the same people as IB but who knows. All just my opinion.
Looked into Alpaca a while back, decided it wasn't usable. API is only one of many considerations. I identified no less than four dealbreakers with Alpaca: no portfolio margin no direct routing max 200 messages per minute (not a typo, minute not second) privacy concern with client id sent to MMs with each order Alpaca's whole business model is questionable IMO. Commission free algo trading? Wholesalers don't want to trade against people who have an edge. How long do you think alpaca will be able to keep selling money losing flow before they get cut off?
Yeah, they did. Might have changed since then but I recommend anyone who cares to ask them what the policy is.