You're right.  I only those three as big tech companies and the ease of use of their platforms. 

Volatility can be fixed by automatic hedging bots designed for companies, so that they never get affected negatively. But the real problem is that, transaction confirmation speed here. It's too slow really.

It can be done, but I don't think this is particularly useful to adoption, especially if it's done through payment processors that just dump directly to fiat. We saw a lot of merchants adding Bitcoin payment options throughout the 2014-2015 bear market, and I don't think it drove adoption.

Seeing it as a merchant payment option might help overall BTC recognition, but as a consumer, it wouldn't make me think, "I better go out and buy some BTC so I can spend it on Uber." Especially if I knew anything about it and took into account the costs of acquiring BTC. And the fees to spend it on low-cost consumer payments. It doesn't make much sense.

It would be interesting if these companies accepted BTC and then also began including it in their investment portfolios. That would definitely have an effect on supply. But I don't know how likely that is.

This would definitely change things and I am sure, a lot of BTC enthusiast will use this function. However, one issue for the majority is, that the BTC price is fluctuating quite a lot, which makes a everyday usage of the coin difficult.

if they would accept bitcoin, i don't think it will be a game changer unless, there companies made  an innovation, that it is only meant for bitcoins. that course could be a game changer, however it will depend on the market where they are located, for example uber, uber here in my country has some problems with the current government, and thankfully it is already been settled, then next, is the patronage of people to bitcoins, there are only a handful of people who lives in the city, with knowledge of bitcoins, and has trust on uber, so their market  is too low for us. lyft however is not here in my country. as for paypal, i think people with bitcoins, would rather transfer their bitcoins via wallet, instead of giving their address to paypal, since paypal is a different platform. if they could only companies would think up of ways on how they can also serve, people with bitcoins and we can see that we can all benefit from it, it only means that they will gain customers, and probably it will be a game changer, in which others will follow.

A big thing I have been thinking about recently is that businesses accepting Bitcoin is less about getting companies to accept Bitcoin so as to grow the community and more to cater to existing Bitcoin users. Even if they start to accept Bitcoin, it maybe increases the speculation value but people will just keep using the same old systems they used to be using. There may be "new" users using the new payment methods, but the real size of the community likely doesn't grow significantly.

Lets just assume what you are saying is true. If these companies start accepting bitcoin then the price of bitcoin will increase by atleast 4 to 5 times. These companies have millions of customers from around the world. As they introduce a new mode of payment the customers attraction will go towards bitcoin. As bitcoin is already famous people would want to buy bitcoins and hence there will be huge crowd on the buy list of bitcoin.
This will increase the price of bitcoin to its peak and then God knows what will happen.

Maybe, but they won't any time soon, so better waste your brain with something more useful.

Uber may accept BTC in the near future but Paypal?? I dont think they will ever accept BTC, they think BTC is a competitor for their shitty services. But they dont know that BTC is much more than that. I feel Amazon or eBay will become a bigger impact than Paypal's acceptance.