Yes, I calculated that.  You can check the spreadsheet to play with the numbers.  Firstly, 191 GB blocks aren't a possibility.  At 31 GB blocks we'd catch up to 100% of the worldwide non-bitcoin transaction volume even accounting for the growth of that number.  There's no way that many businesses/people are going to switch to Bitcoin in 30 years.  If we got 5% that'd be awesome, and that's 900mb blocks.  900mb blocks may sound terrifying, but even without major improvements to the protocol businesses and nonprofits like the EFF could run nodes for less than $2000 a month.  That's a rounding error in most business' IT budgets, and nodes would be running in every nearly every country on the planet by that point, massively geographically distributed.  Early adopters could easily run a node for the rest of their life without breaking a sweat.  That doesn't seem scary to me at all for 5% of the world's transaction volume.  Shit, if we had 5% of the world's transaction volume, the price would probably be upwards of $60,000 per BTC, or more.

Secondly, 50% growth year over year is offset by a 17% decline in bandwidth and hard drive prices, so ~33% increase per year in node operational costs.  Bitcoin prices have been increasing by 44% per year for the last 4 years, so for anyone who actually holds more than a few bitcoins, the node costs remain trivial.

Thirdly, 50% growth year over year for 10-30 years requires a continuous agreement of 60% of the miners for that full time period, with no miner waving.  Historically getting 60% of miners to agree to signal the same thing has been very difficult, much less getting them to continue supporting it for a year.  All it would take is one miner agreeing that node costs were becoming problematic and switching his vote and the growth would stall dramatically.

So yeah, those numbers look scary at first.  They did for me too.  But given the possible rewards for Bitcoin, it really isn't that scary.