Sure, your phone is kind of fast… but it could be faster. A lot faster. All of the big wireless carriers are super excited about the whole new network generation of fast, but there’s a hitch: It doesn’t exist yet. But that’s not deterring T-Mobile, which is out there today promising to get you a nationwide 5G network while Verizon and AT&T are still pulling their metaphorical shoes on.

T-Mobile CEO John Legere and CTO Neville Ray made their promises today with a video and corporate blog post.

Legere began by singing the praises of the future — and, as he does, waving off and mocking the efforts of his competitors.

“5G will be amazing, and we can’t even imagine all the cool stuff it will bring, just like with our earlier network innovations,” he said. “That’s why truly mobile 5G has to be nationwide — period, the end.”

Then, he mentioned AT&T’s trial efforts, claiming to quote media that found AT&T’s plan, “bull**it,” “fake,” and, “ruining 5G.” He followed that up by mocking Verizon’s statements that fixed 5G networks could be a reliable alternative for cable at home.

“Of course,” he added, “that should be really fun to watch, because if there’s anyone consumers hate more than the duopoly, it’s probably big cable.”

(He’s not wrong: Consumers do, in fact, hate their cable companies.)

Legere then explained why he thinks AT&T and Verizon’s high-frequency strategy sucks: “It’s basically a series of hotspots,” he said. “That’s no solution for mobile 5G coverage!”

MORE: What the heck is 5G, anyway?

Ray echoed the sentiment in his blog post. “5G is going to be AMAZING — maybe the most transformative technology of our lifetime,” he began. “Nationwide 5G coverage will drive endless possibilities, and yes, the future is kick-ass!”

Ray and Legere are alone in their enthusiasm for the 5G future. The wireless carriers and the FCC — both under former chair Tom Wheeler and also current chair Ajit Pai — are excited about the potential for pervasive, super-speedy networks.

But then Ray continues into a fact vs. fiction section that’s a little misleading with its facts. Following Legere’s lead, he bashes AT&T and Verizon’s baby steps into 5G to date.

“Last week AT&T introduced #Fake5G,” Ray says, “and tried to confuse consumers and distract from the fact that their network is losing to T-Mobile.”

And on the other end, “Verizon is getting their ass kicked so bad in wireless they’re banking on ‘Fixed 5G’ — wired broadband replacement one home at a time — to help them compete with the only companies people hate more than Verizon.”

The first big problem with T-Mobile’s promise is that there is no unified 5G standard yet. AT&T and Verizon are launching limited trials in certain hot-spots because they’re still trying to work out what the best approach for their massive networks actually is — what works fastest, most reliably, at the least cost.

3GPP, the international consortium that hammers out and defines the technical details of mobile standards, is still working on 5G. In a February update, the group said that specifications for the first phase of 5G — the part where it actually has a logo and gets to be a real thing — will be ready in June 2018.

Ray acknowledges that, writing “As 5G standards are defined, chipsets are delivered, and equipment comes to market, we expect to be 3GPP certified and be able deploy 5G on clean spectrum … We’ll expect all this to begin in 2019 and target 2020 for a full nationwide rollout.”

This timeline, however, is almost certainly not unique to T-Mobile; most carriers are probably going to try to accomplish something similar, if 3GPP finalizes its specs when predicted.

Meanwhile, T-Mobile’s repeated assertion that there is no “5G and not 5G spectrum” are true. You can build a next-generation network either at the low end or the high end of available radio frequencies that underpin all modern communications, or even some of the spectrum in between. Some of the chunks of spectrum the FCC has assigned to “advanced wireless technologies” are in the 600 MHz range that T-Mobile just bought a lot of, and some are in very high-frequency ranges previously considered unusable. Building a true national and international 5G network will require carriers to develop the ability to take advantage of all of it.

And while we’re not usually in the business of defending Verizon from, well, anything, T-Mobile’s implication that its competitor is foolish for trying to replace fixed broadband with 5G is a bit unfair. Millions of Americans still haven’t been reached by decent — or any — home broadband. Running new wires to rural areas is expensive and logistically complicated; new wireless technologies may be the best hope for narrowing the digital divide, especially for folks who live in rural areas or on tribal lands.

So will it be exciting when T-Mobile does manage to develop and launch the first generation 5G network in 3 or 4 years? Sure! But by then it probably won’t be as alone as its leadership claims to be.

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