Akamai is their ceiling in CDN because they have a much higher value segment of the business, representing a drastically larger share of all dollars in the CDN space. Their business is nine times the size of Cloudflare because their customers are far more lucrative.

If Cloudflare holds onto all of their already considerable number of customers, and then kills Akamai and somehow takes all of Akamai's business, the combination will be a mere 10% larger than Akamai already is now. There is your general indie ceiling in action, with all segments combined (and Cloudflare isn't going to monopolize the entire CDN business besides).

All you need to know to spot the independent CDN ceiling is that Cloudflare + Fastly + Akamai = $3.6 billion in sales (with the understanding that it's a slowly increasing ceiling, as the CDN market is still growing). The ceiling in that space for Cloudflare just can't realistically be much larger than that combined group and that's not much larger than where Akamai is already at. The only way this isn't the case, is if you project Cloudflare knocks off most competitors and takes the market (they can't, Amazon, Microsoft, Google among other giants, are standing in the way of that outcome).

It'll take Cloudflare a small lifetime to get to $3 billion in sales in the CDN space at the rate they're growing (they're adding ~$8m-$10m per quarter in growth (all of which obviously isn't CDN), so maybe it'll only take a few decades with some compounding). It took Akamai 22 years to get there with very high value customers and a pretty nice open field for many of those years.

Akamai in absolute dollar terms is growing faster than Cloudflare + Fastly combined. The CDN ceiling is actually running away from Cloudflare at present. That shouldn't be happening.

Cloudflare knows full well CDN isn't their brightest business future. It's why so much of their expansion effort is going into everything else. Given the way they price-structured their CDN from day one, Cloudflare has always known CDN was a lure and the upside was in sprawling outward from it. Come for the CDN, stay for the workers or whatever preferably higher margin thing we can sell you on. It's also why they're not interested in / worried about trying to make money on domain registrations, as with SSL before that. They'll happily murder the margins in foreign services all day long (areas where they don't compete, but there is margin to wipe out cost effectively, and with customers to lure in), so long as they can occasionally launch a new service where they have a distinct advantage and can convert their base to use it and increase total revenue per customer in the process.

What would be a better path: if Cloudflare could own a big part of Akamai's CDN business by trying to aggressively climb up the ladder from an unassailable price-value position Akamai doesn't want to go down to, like an ARM eating an Intel from the feet upward; or just leave the snoring giant alone to keeping snoozing in his enterprise tower while Cloudflare busies itself sprawling out in many directions, leveraging the volume of customers that Akamai doesn't want to (and or can't) go after because they're not viewed as lucrative enough? I think what Cloudflare can find outside of the CDN business, is likely to be more valuable than what's inside the CDN business, very long-term speaking.

And if you're Akamai and you let Cloudflare get far enough along with that sprawling (likely already too late), how about if they drop your CDN legs out from under you. Cloudflare builds out many other legs to stand on, so they flip the switch on the margin and kill the CDN market for the independents, as they were willing to do with domains and SSL. Free CDN, all tiers, all features. They can't do that today, they might be able to do it tomorrow. The CDN market becomes the SSL market, and as a totally free lure it accelerates a rush into Cloudflare's other more exclusive services (including for larger, lucrative enterprise customers). Surely this switch has been pondered inside of Cloudflare, road-mapped as a potential.